Sustainable Last-Mile Logistics in Economics Studies: A Systematic Literature Review
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsClarity of presentation: Ensure that the structure of the document is clear and consistent, making it easier for the reader to understand.
Greater emphasis on practical implications: Although the work addresses theoretical and conceptual aspects of sustainable last mile logistics, it would be beneficial to include a more detailed discussion on the practical implications of the findings for companies, policy makers and other relevant actors.
Consider the inclusion of case studies: Incorporating concrete examples or case studies could enrich the work by providing practical examples of the implementation of sustainable measures in last mile logistics
Author Response
Dear anonymous reviewer,
Thank you for your feedback on the manuscript. We carefully read your observations: please find below our responses to your comments.
Kind regards,
the authors.
Referee report 1
- Clarity of presentation: Ensure that the structure of the document is clear and consistent, making it easier for the reader to understand.
Thank you for the suggestion, we proofread the manuscript and we tried to make it easier to read and understand the work.
- Greater emphasis on practical implications: Although the work addresses theoretical and conceptual aspects of sustainable last mile logistics, it would be beneficial to include a more detailed discussion on the practical implications of the findings for companies, policy makers and other relevant actors.
We think the conclusion of the manuscript can really benefit from this suggestion: we included some examples of practical implications in that section.
- Consider the inclusion of case studies: Incorporating concrete examples or case studies could enrich the work by providing practical examples of the implementation of sustainable measures in last mile logistics.
Thank you for the suggestion: we enriched the conclusions with some practical examples.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe title of the manuscript seems to be misleading, as it does not clearly convey the context of the manuscript. It is better to make it clear in the title - whose economic perspective it is, the service provider or the community. The content covered in the manuscript appears to be relevant to the journal audience.
The manuscript is aimed at providing a systematic literature review on environmentally sustainable last-mile logistics.
The abstract section contains enough information to inform a potential reader about the content of the manuscript. However, the contributions of the paper are not clearly stated. The contributions stated in the abstract section are, in fact, the steps undertaken to reach the outcome of the review. The abstract needs to be shortened a bit.
The introduction presents a well-researched write-up and clarifies the context of the study. However, the literature review (in the Introduction and Review sections) needs to be strengthened by including recent articles related to the topic of the study. Besides, an explanation of the shortcomings of the existing review studies, and how this review study overcomes those shortcomings, should be provided.
The methodology section gives an adequate level of detail on the study selection exercise done in the review. However, it seems that most of the selected studies are from European countries, apart from a few from the Americas. There are relevant recent studies from several countries, such as Australia, Japan and New Zealand, that could have been included in the review. Providing a density map showing the locations of the selected studies would have given an understanding of the extent of work done in various parts of the world.
The outcome of the review should be tied into the objective of the study mentioned earlier in the manuscript.
The conclusion section is well written.
The manuscript is written satisfactorily, and the research done is interesting, with high interest likely to be drawn from the readers of this work.
There were a few grammatical errors noticed in the manuscript (highlighted a few of them). Please re-read the manuscript, rectify those errors, and refer to the attached PDF for additional comments.
Comments for author File: Comments.pdf
Minor corrections needed.
Author Response
Dear anonymous reviewer,
Thank you for your feedback on the manuscript. We carefully read your observations: please find below our responses to your comments.
Kind regards,
the authors.
Referee report 2
- The title of the manuscript seems to be misleading, as it does not clearly convey the context of the manuscript. It is better to make it clear in the title - whose economic perspective it is, the service provider or the community. The content covered in the manuscript appears to be relevant to the journal audience.
Thank you for your suggestion. We modified the title of the manuscript to better reflect the content and the scope of the work.
- The manuscript is aimed at providing a systematic literature review on environmentally sustainable last-mile logistics.
The abstract section contains enough information to inform a potential reader about the content of the manuscript. However, the contributions of the paper are not clearly stated. The contributions stated in the abstract section are, in fact, the steps undertaken to reach the outcome of the review. The abstract needs to be shortened a bit.
We agree with you, the abstract is now shorter and we removed the description of the methodology.
- The introduction presents a well-researched write-up and clarifies the context of the study. However, the literature review (in the Introduction and Review sections) needs to be strengthened by including recent articles related to the topic of the study. Besides, an explanation of the shortcomings of the existing review studies, and how this review study overcomes those shortcomings, should be provided.
The methodology section gives an adequate level of detail on the study selection exercise done in the review. However, it seems that most of the selected studies are from European countries, apart from a few from the Americas. There are relevant recent studies from several countries, such as Australia, Japan and New Zealand, that could have been included in the review. Providing a density map showing the locations of the selected studies would have given an understanding of the extent of work done in various parts of the world.
Thank you for your feedback. We are aware of the limits imposed by the rigidity of the systematic review protocol that only allows us to include papers extracted from Web of Science (Section 2 describes the process in detail)). For methodological reasons, we cannot add publications out of the analysed time-frame (or modify the set discretionally). .
However, we acknowledge that using a single platform (namely, Web of Science) may have increased the exposure to a geographical bias in the selection process. The existence of geographical biases in peer-reviewed scientific publications is an issue (Skopec et al., 2020), and there is evidence of biases against research produced in non-Western countries and not in English in the leading research platforms (i.e., Scopus and Web of Science) (Tennant, 2020).Therefore, we have decided to put a methodological note in the methodology section.
References:
Skopec M, Issa H, Reed J, Harris M. The role of geographic bias in knowledge diffusion: a systematic review and narrative synthesis. Res Integr Peer Rev. 2020 Jan 15;5:2. doi: 10.1186/s41073-019-0088-0. PMID: 31956434; PMCID: PMC6961296.
Tennant JP (2020) Web of Science and Scopus are not global databases of knowledge. European Science Editing 46: e51987. https://doi.org/10.3897/ese.2020.e51987
- The outcome of the review should be tied into the objective of the study mentioned earlier in the manuscript.
Thank you for the suggestion. We rephrased as follows in Par.4 line 74:
Original version: “This review aims to investigate the state-of-the-art to the last leg of the supply chain (i.e., the last-mile logistics) taking place in the urban context”.
Revised version: “The review aims to investigate the state-of-the-art literature on sustainable last-mile logistics. We scanned literature to detect trends and significant gaps in economic research dealing with urban deliveries, especially from a public perspective.”
- The conclusion section is well written.
The manuscript is written satisfactorily, and the research done is interesting, with high interest likely to be drawn from the readers of this work.
Thank you for your appreciation. The conclusion of the revised manuscript was modified in order to comply with the observations received by other reviewers, but still keeping the original style.
- There were a few grammatical errors noticed in the manuscript (highlighted a few of them). Please re-read the manuscript, rectify those errors, and refer to the attached PDF for additional comments.
Thank you for your help in revising the manuscript. We made the corrections, and we considered your suggestions to further improve the manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsPaper Title: Economic perspectives in sustainable last-mile logistics: a systematic literature review
The present research attempts to provide a systematic literature review (SLR) on environmentally sustainable last-mile logistics using 108 research papers. The SLR contributes in three ways (a) it focuses on last-mile logistics having sustainable measures adopted by companies, governments (mainly local) and supra-national institutions; (b) classifies the literature into five categories (i.e., agents’ preferences and choices, shared logistics, stakeholders, studies on vehicles, and policy and decisions) clarifying the implications of the public economics analysis; and (c) identifying the gaps and limitations of the existing literature and proposing potential issues for future research insights.
General comments:
1) The introduction section looks weak, it focuses more on COVID-19 and its effects.
2) The methodology section does not follow the standard procedure and hence may be tuned.
3) Please refer to ‘…we chose to focus attention primarily on environmental sustainability,…, ‘which differs from the economic perspective of the present research.
4) Please refer to ‘This review aims to investigate the state-of-the-art to the last leg of the supply chain (i.e., the last-mile logistics) taking place in the urban context.’ Looks very broad and differs from the manuscript title.
5) Figure 2. Number of papers per year in our final pool of articles includes repeated captions and named Figure 1,
6) Section Heading ‘3. Topics’ may be suitably modified
7) The transportation of blood products/organs to the transfusing health facility as last-mile delivery is missing in the present SLR.
8) The use of Motorbikes as a last-mile delivery has not been included in the present SLR.
9) The research papers on Last Mile Delivery Mode selection may have been included
10) The analysis carried out from an economic perspective in the present form lacks clarity and depth.
11) Authors may discuss the problems and issues related to last-mile delivery in an urban context and may provide innovative solutions to them.
12) In the present form, the gathered information, presentation, and analysis look weak. For instance, please refer to ‘The use of non-financial incentives (i.e., information messages, order of delivery options, social media, and social norms) is analyzed by Rai et al. (2021).’ Does not clarify that non-financial incentives drive sustainable e-commerce delivery. The results are derived from the empirical analysis, etc.
13) The research contribution looks limited.
Comments on the Quality of English LanguageThe manuscript has some typos and grammatical mistakes, hence careful editing is needed.
1) Please refer to“….2019 (IEA, 2020). Urban deliveries…..” Spacing between the sentences may be reduced. Similarly, “two separate extractions: one performed in”
2) ‘…after the reading – seem to represent the most discussed topics with an…’ should be ‘… after reading – seemed to represent the most discussed topics from an..’
3) 'Last-mile logistics has a high impact on everyday life of consumers,..' should be 'Last-mile logistics has a high impact on the everyday lives of consumers,..'
4) '... in order to make accessible the work to ....' should be '... in order to make the work accessible to ....'
5) '...increase sustainability, or to whether it should be an....' should be '...increase sustainability, or whether it should be an.....'
6) '... preferences may also regard the way ...' should be '... preferences may also affect the way ...'
7) 'Ghaderi et al. (2022) made clear...' should be 'Ghaderi et al. (2022) made it clear...'
8) '...if most of the companies collect data privately and hardly share them' should be '...if most of the companies collect data privately and hardly share it'
Author Response
Dear anonymous reviewer,
Thank you for your feedback on the manuscript. We carefully read your observations: please find below our responses to your comments.
Kind regards,
the authors.
Referee report 3
Paper Title: Economic perspectives in sustainable last-mile logistics: a systematic literature review
The present research attempts to provide a systematic literature review (SLR) on environmentally sustainable last-mile logistics using 108 research papers. The SLR contributes in three ways (a) it focuses on last-mile logistics having sustainable measures adopted by companies, governments (mainly local) and supra-national institutions; (b) classifies the literature into five categories (i.e., agents’ preferences and choices, shared logistics, stakeholders, studies on vehicles, and policy and decisions) clarifying the implications of the public economics analysis; and (c) identifying the gaps and limitations of the existing literature and proposing potential issues for future research insights.
General comments:
- The introduction section looks weak, it focuses more on COVID-19 and its effects.
We revised the manuscript taking into account your observation. However, it’s worth to specify that consequences of the covid-19 pandemic motivate the large majority of most recent papers and that’s why the pandemic is a prevalent topic in the introduction.
- The methodology section does not follow the standard procedure and hence may be tuned.
If we understood well, you refer to the organisation of the section. Guidelines for the authors of “Sustainability” prescribe the following sections: front matter, literature review sections and the back matter (i.e. Supplementary Materials, Acknowledgments, Author Contributions, Conflicts of Interest, References). Our “literature review sections” follow the steps suggested in Lagorio, A., Pinto, R. and Golini, R. (2016), "Research in urban logistics: a systematic literature review", International Journal of Physical Distribution & Logistics Management, Vol. 46 No. 10, pp. 908-931. https://doi.org/10.1108/IJPDLM-01-2016-0008 Research in urban logistics: a systematic literature review | Emerald Insight. In their work, the authors specify that “The SLR is selected as the research method for this study because of the nature of the research questions, which aim at understanding trends and detecting existing gaps in the scientific literature. […] This study followed the guidelines provided in the most prominent articles (Kitchenham and Charters, 2007; Kitchenham and Brereton, 2013; Touboulic and Walker, 2015; Tranfield et al., 2003) to devise a robust and replicable study. In particular, a three-step protocol was developed to identify a valid procedure for performing an automated research so the SLR can be replicated by other researchers (Kitchenham and Charters, 2007).” We found the method strong and suitable for our analysis too.
- Please refer to ‘…we chose to focus attention primarily on environmental sustainability,…, ‘which differs from the economic perspective of the present research.
We reformulated the paragraph:
“Since transportation in general is one of the most polluting sectors in terms of GHG emissions and plays a significant role in the energy transition process, we chose to focus attention primarily on environmental sustainability, although the concept of sustainability is arguably quite broad and may encompass other dimensions (e.g. economically or financially sustainable). “
as follows:
“The concept of sustainability may encompass several dimensions (e.g. environmental, social, or financial sustainability). Still, since transportation is one of the most polluting sectors in terms of GHG emissions and plays a significant role in the energy transition process, the present review focuses mainly on issues connected to environmental sustainability, adopting an economic point of view for the analysis of existing literature on urban last-mile logistics.”
- Please refer to ‘This review aims to investigate the state-of-the-art to the last leg of the supply chain (i.e., the last-mile logistics) taking place in the urban context.’ Looks very broad and differs from the manuscript title.
“This review aims to investigate the state-of-the-art to the last leg of the supply chain (i.e., the last-mile logistics) taking place in the urban context”.
was rephrased as follows:
“The review aims to investigate the state-of-the-art literature on sustainable last-mile logistics. We scanned literature to detect trends and significant gaps in economic research dealing with urban deliveries, especially from a public perspective.”
- Figure 2. Number of papers per year in our final pool of articles includes repeated captions and named Figure 1
Thank you, we modified the labelling.
- Section Heading ‘3. Topics’ may be suitably modified
Thank you for your suggestion, we agree it was not sufficiently clear: the title is now “Clustering of the research topics”, which is more representative of what is represented in the related paragraph.
- The transportation of blood products/organs to the transfusing health facility as last-mile delivery is missing in the present SLR.
Thank you for your comment. Unfortunately, our pool had no papers on blood or organ donation logistics. This might be explained by two possible reasons.
On the one hand, human health logistics (e.g., organ transplants, vaccines or particular drugs) is characterised by very peculiar features which set this type of logistics away from the logistics of consumption goods, e.g. low frequency of deliveries and high time pressure to perform the delivery. Considering organ donations, it is crucial to have qualified medical staff to manage the transportation of the organs from hospital A to hospital B (Genç, 2008). In the case of vaccines, the distribution process may be influenced by the fact that decision power over the delivery is spread among drug suppliers, public health organisations or donors, and final receivers (Westerink-Duijzer et al., 2018). Therefore, the logistics of blood products/organs (and similarly emergency or disaster logistics and vaccine delivery) differs a lot from the logistics of commodities operated under ordinary conditions.
On the other hand, our review focuses on the urban context - whereas, in many cases, human health logistics involve longer supply chains - and decarbonising solutions. We are aware of some pioneering works on the decarbonisation of healthcare facilities' transport activities (Rasheed et al., 2021; Jalilvand et al., 2023), but this stream of literature is still in its early stages.
References
Genç R. The logistics management and coordination in procurement phase of organ transplantation. Tohoku J Exp Med. 2008 Dec;216(4):287-96. doi: 10.1620/tjem.216.287. PMID: 19060443.
Jalilvand S, Heidari S, Mohammadnazari Z, Aghsami A, Rabbani E, Rabbani M. A Bi-objective Organ Transplant Supply Chain Network with Recipient Priority Considering Carbon Emission Under Uncertainty, a Case Study. Process Integr Optim Sustain. 2023 Feb 15:1–19. doi: 10.1007/s41660-023-00314-1. Epub ahead of print. PMCID: PMC9930023.
Rasheed F N, Baddley J, Prabhakaran P, De Barros E F, Reddy K S, Vianna N A et al. Decarbonising healthcare in low and middle income countries: potential pathways to net zero emissions BMJ 2021; 375 :n1284 doi:10.1136/bmj.n1284
Westerink-Duijzer, L. & Jaarsveld, Willem & Dekker, Rommert. (2018). Literature Review - the vaccine supply chain. European Journal of Operational Research. 10.1016/j.ejor.2018.01.015.
8) The use of Motorbikes as a last-mile delivery has not been included in the present SLR.
We add them to the list (page 12).
9) The research papers on Last Mile Delivery Mode selection may have been included
Thank you for your comment. We preferred not to create a separate section for the choice of the delivery mode as we reckon that throughout the review this topic has been already touched in the discussion of clusters.
10) The analysis carried out from an economic perspective in the present form lacks clarity and depth.
We followed your suggestions and we performed a re-writing of some of the sections in order to improve the clarity of the messages. In particular, we extended the discussion provided in the conclusions to underline which are the “take away” concepts found thanks to the review process.
11) Authors may discuss the problems and issues related to last-mile delivery in an urban context and may provide innovative solutions to them.
The article presents a literature review: the scope of the work is to identify the most discussed topic in scientific literature regarding sustainable last mile logistics. By nature, this analysis leads to the presentation of a number of problems and also of a number of solutions, which are discussed in the scientific papers analysed. Finding solutions for practical issues calls for a proper scientific work, which is out of the scope of the literature review. However, to increase the power of the work and to stimulate the debate, we include some considerations in the concluding paragraph.
12) In the present form, the gathered information, presentation, and analysis look weak. For instance, please refer to ‘The use of non-financial incentives (i.e., information messages, order of delivery options, social media, and social norms) is analyzed by Rai et al. (2021).’ Does not clarify that non-financial incentives drive sustainable e-commerce delivery. The results are derived from the empirical analysis, etc.
The article has been modified as follows:
Previous version:
“The use of non-financial incentives (i.e., information messages, order of delivery options, social media, and social norms) is analysed by Rai et al. (2021). In their study, presenting an informative message to consumers help them to grasp the environmental benefits of opting for a slower delivery alternative and to bridge the time gap between the moment of choice and the one in which its impacts are manifested.”
Modified version:
“The use of non-financial incentives (i.e., information messages, order of delivery options, social media, and social norms) to push sustainable e-commerce delivery options is analyzed by Rai et al. (2021). In the online experimental study, presenting an informative message to consumers helps them to grasp the environmental benefits of opting for a slower delivery alternative and to bridge the time gap between the moment of choice and the one in which its impacts are manifested”.
Concluding, we proofread the manuscript to fix typos and grammatical errors. Thank you for your contribution.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThank you for updating the manuscript. However, few comments referring to add new section/ area of research have been skipped wisely.
(a)Please refer to my earlier comment "The methodology section does not follow the standard procedure and hence may be tuned" The authors’ reply of “We found the method strong and suitable for our analysis too.” is not convincing. The paper pool collection drops from 583 to 108 i.e. 583-365-161-108 at each stage. The percentage of paper exclusion in each stage ranged from 33% to 56%.
(b) The changed title, "Sustainable last-mile logistics in economics studies: a systematic literature review. “and stated aim in the abstract, "This study aims to provide a systematic literature review of studies having as the main topic environmentally sustainable last-mile logistics."' are not in the same line.
(c)Further “Sustainable last-mile logistics in economics studies”, The “economic studies” is misguiding.
(d) Please refer to “This study aims at detecting the different topics and policies discussed in the literature and it suggests how to incorporate them in creating new measures and policies or revamping current ones’ does not read well. The context of studies will help readers to understand well.
(e)There are several sentences which sound incomplete or need further context to understand, for instance
(1)‘The scope of this review is to detect the main issues discussed in the literature and to find gaps worth developing in the future.”
(f) There are several research articles out of the reviews from the year band of 2017- November 022, for instance:
(a) Bosona, T., 2020. Urban freight last mile logistics—Challenges and opportunities to improve sustainability: A literature review. Sustainability, 12(21), p.8769.
(b) Butrina, P., del Carmen Girón-Valderrama, G., Machado-León, J.L., Goodchild, A. and Ayyalasomayajula, P.C., 2017. From the last mile to the last 800 ft: Key factors in urban pickup and delivery of goods. Transportation Research Record, 2609(1), pp.85-92.
(c) Janjevic, M., Winkenbach, M. and Merchán, D., 2019. Integrating collection-and-delivery points in the strategic design of urban last-mile e-commerce distribution networks. Transportation Research Part E: Logistics and Transportation Review, 131, pp.37-67.
(g) Please refer to "...as we detected a spike in interest in the topic starting that year.' however Figure 2 indicates otherwise in the year 2017 hence may be modified
Comments on the Quality of English Language
Thanks for the updated version. The paper needs careful reading to improve its readability.
Author Response
Dear Reviewer,
We appreciate your effort in revising the manuscript. We also thank you for the speed in sending the second review.
Please find below our answers.
Kind regards,
the authors
Referee report
Thank you for updating the manuscript. However, few comments referring to add new section/ area of research have been skipped wisely.
(a)Please refer to my earlier comment "The methodology section does not follow the standard procedure and hence may be tuned" The authors’ reply of “We found the method strong and suitable for our analysis too.” is not convincing. The paper pool collection drops from 583 to 108 i.e. 583-365-161-108 at each stage. The percentage of paper exclusion in each stage ranged from 33% to 56%.
We want to answer your point in two separate stages:
1) Ex ante choice of methodology. Before starting the work, we checked literature reviews performed in the sector (or similar sectors) and we found an example that was close to our explorative idea (Lagorio, A., Pinto, R. and Golini, R., 2016, as mentioned in our previous response). Their work was based on methodologies approved in other works (Kitchenham and Charters, 2007; Kitchenham and Brereton, 2013; Touboulic and Walker, 2015; Tranfield et al., 2003) as we mentioned in the previous answer. Furthermore, the same methodology was used in a recent review published in “Applied Energy” by a recognized pool of researchers led by UCL university under the Global Observatory on P2P energy training, financed by the International Energy Agency (Dudjak V. et al., 2021). Therefore, the methodology we used in this work is widely accepted and recognized by scientific journals: the presence of a wide sample of peer reviewed scientific publications based on the same steps support our statement.
2) Ex post results. You observe that there is a great drop in the number of papers we include in the review after the inclusion/exclusion steps. This observation is of course correct, but the considerable decrease is not surprising, if we consider the reason underlying the exclusion of the works. Focusing on the drop between step 2 and step 3 (where the decrease is very intense), for example, citing the manuscript, par. 2.2 “We discarded 204 papers that, despite automatic inclusion performed by Web of Science, were related to topics beyond our field of interest. These papers were either out of scope (i.e., the wording misled the automatic research), or their focus was different from urban last-mile logistics (e.g., works dealing with rural last mile or private vehicles”: considering that the papers were studying other topics, there is no reason to review them.
Let us also specify that finding lacks in the literature or finding works which - in the end - are out of our scope strength our suspect, i.e. the topic is not satisfactory covered by scientific literature.
(b) The changed title, "Sustainable last-mile logistics in economics studies: a systematic literature review. “and stated aim in the abstract, "This study aims to provide a systematic literature review of studies having as the main topic environmentally sustainable last-mile logistics."' are not in the same line.
Thank you. We specified “with the perspective of economic studies” in the abstract.
(c)Further “Sustainable last-mile logistics in economics studies”, The “economic studies” is misguiding.
We want to review the works that are carried out with an economic perspective - and this is clearly stated in the manuscript. We think that “economics studies” can properly identify the studies carried out in the field of economics, but we are open to your suggestions to improve the accuracy of the title.
(d) Please refer to “This study aims at detecting the different topics and policies discussed in the literature and it suggests how to incorporate them in creating new measures and policies or revamping current ones’ does not read well. The context of studies will help readers to understand well.
We specified “for last mile logistics in the urban area” in the revised version.
(e)There are several sentences which sound incomplete or need further context to understand, for instance (1)‘The scope of this review is to detect the main issues discussed in the literature and to find gaps worth developing in the future.”
We modified the sentence in the revised version.
(f) There are several research articles out of the reviews from the year band of 2017- November 022, for instance:
(a) Bosona, T., 2020. Urban freight last mile logistics—Challenges and opportunities to improve sustainability: A literature review. Sustainability, 12(21), p.8769.
Reviews are excluded from the analysis (see par. 2.2).
(b) Butrina, P., del Carmen Girón-Valderrama, G., Machado-León, J.L., Goodchild, A. and Ayyalasomayajula, P.C., 2017. From the last mile to the last 800 ft: Key factors in urban pickup and delivery of goods. Transportation Research Record, 2609(1), pp.85-92.
(c) Janjevic, M., Winkenbach, M. and Merchán, D., 2019. Integrating collection-and-delivery points in the strategic design of urban last-mile e-commerce distribution networks. Transportation Research Part E: Logistics and Transportation Review, 131, pp.37-67.
We can not include in the list papers which don’t result from the process declared in the methodology. The research is based on Web of Science (see footnote 1).
(g) Please refer to "...as we detected a spike in interest in the topic starting that year.' however Figure 2 indicates otherwise in the year 2017 hence may be modified
Thank you for your suggestion, we modified the sentence that was misleading.
Author Response File: Author Response.pdf