How to format your references using the Challenges citation style

This is a short guide how to format citations and the bibliography in a manuscript for Challenges. For a complete guide how to prepare your manuscript refer to the journal's instructions to authors.

Using reference management software

Typically you don't format your citations and bibliography by hand. The easiest way is to use a reference manager:

Paperpile	The citation style is built in and you can choose it in Settings > Citation Style or Paperpile > Citation Style in Google Docs.
EndNote	Find the style here: output styles overview
Mendeley, Zotero, Papers, and others	The style is either built in or you can download a CSL file that is supported by most references management programs.
BibTeX	BibTeX syles are usually part of a LaTeX template. Check the instructions to authors if the publisher offers a LaTeX template for this journal.

Journal articles

Those examples are references to articles in scholarly journals and how they are supposed to appear in your bibliography.

Not all journals organize their published articles in volumes and issues, so these fields are optional. Some electronic journals do not provide a page range, but instead list an article identifier. In a case like this it's safe to use the article identifier instead of the page range.

A journal article with 1 author

Koroshetz, W.J. Perspective: Time to Tackle Blood Pressure. Nature 2014, 510, S4.

A journal article with 2 authors

Costa, S.; Shaw, P. Chromatin Organization and Cell Fate Switch Respond to Positional Information in Arabidopsis. Nature 2006, 439, 493–496.

A journal article with 3 authors

Atallah, B.V.; Scanziani, M.; Carandini, M. Atallah et al. Reply. Nature 2014, 508, E3.

A journal article with 4 or more authors

Wild, C.; Huettel, M.; Klueter, A.; Kremb, S.G.; Rasheed, M.Y.M.; Jørgensen, B.B. Coral Mucus Functions as an Energy Carrier and Particle Trap in the Reef Ecosystem. Nature 2004, 428, 66–70.

Books and book chapters

Here are examples of references for authored and edited books as well as book chapters.

An authored book

Stegmann, J.P. Strategic Value Management; John Wiley & Sons, Inc.: Hoboken, NJ, 2009; ISBN 9781118268087.

An edited book

Pelekis, N. Mobility Data Management and Exploration; Theodoridis, Y., Ed.; Springer: New York, NY, 2014; ISBN 9781493903917.

A chapter in an edited book

Liang, J.Z.; Corso, N.; Turner, E.; Zakhor, A. Image-Based Positioning of Mobile Devices in Indoor Environments. In Multimodal Location Estimation of Videos and Images; Choi, J., Friedland, G., Eds.; Springer International Publishing: Cham, 2015; pp. 85–99 ISBN 9783319098609.

Web sites

Sometimes references to web sites should appear directly in the text rather than in the bibliography. Refer to the Instructions to authors for Challenges.

Blog post

Hale, T. Extinct Baby Bird Has Been Stuck in Amber For 100 Million Years Available online: https://www.iflscience.com/plants-and-animals/extinct-baby-bird-has-been-stuck-in-amber-for-100-million-years/ (accessed on 30 October 2018).

Reports

This example shows the general structure used for government reports, technical reports, and scientific reports. If you can't locate the report number then it might be better to cite the report as a book. For reports it is usually not individual people that are credited as authors, but a governmental department or agency like "U. S. Food and Drug Administration" or "National Cancer Institute".

Government report

Government Accountability Office Reports Issued in June 1989; U.S. Government Printing Office: Washington, DC, 1989;

Theses and dissertations

Theses including Ph.D. dissertations, Master's theses or Bachelor theses follow the basic format outlined below.

Doctoral dissertation

Zivkovic, O. Ternary Nanomaterials: Synthesis by Alkalide Reduction and Characterization. Doctoral dissertation, George Washington University: Washington, DC, 2010.

News paper articles

Unlike scholarly journals, news papers do not usually have a volume and issue number. Instead, the full date and page number is required for a correct reference.

New York Times article

Koblin, J. CBS Anchor Bids Farewell, Then Is Asked to Leave. New York Times 2017, B2.

In-text citations

References should be cited in the text by sequential numbers in square brackets:

This sentence cites one reference [1].
This sentence cites two references [1,2].
This sentence cites four references [1–4].

About the journal

Full journal title	Challenges
ISSN (online)	2078-1547
Scope