How to format your references using the Proceedings of the National Academy of Sciences of the United States of America citation style

This is a short guide how to format citations and the bibliography in a manuscript for Proceedings of the National Academy of Sciences of the United States of America (PNAS). 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

J. L. Gill, ECOLOGY. Learning from Africa’s herbivores. Science 350, 1036–1037 (2015).

A journal article with 2 authors

M. Elimelech, W. A. Phillip, The future of seawater desalination: energy, technology, and the environment. Science 333, 712–717 (2011).

A journal article with 3 authors

C.-W. Wang, S.-M. Ka, A. Chen, Robust image registration of biological microscopic images. Sci. Rep. 4, 6050 (2014).

A journal article with 6 or more authors

N. M. Page, et al., Excessive placental secretion of neurokinin B during the third trimester causes pre-eclampsia. Nature 405, 797–800 (2000).

Books and book chapters

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

An authored book

R. M. Khan, Problem Solving and Data Analysis using Minitab (John Wiley & Sons, Ltd, 2013).

An edited book

M. Claypool, S. Uhlig, Eds., Passive and Active Network Measurement: 9th International Conference, PAM 2008, Cleveland, OH, USA, April 29-30, 2008. Proceedings (Springer, 2008).

A chapter in an edited book

X. Wu, D. Z. Chen, K. Li, M. Sonka, “The Layered Net Surface Problems in Discrete Geometry and Medical Image Segmentation” in Algorithms and Computation: 16th International Symposium, ISAAC 2005, Sanya, Hainan, China, December 19-21, 2005. Proceedings, Lecture Notes in Computer Science., X. Deng, D.-Z. Du, Eds. (Springer, 2005), pp. 17–27.

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 Proceedings of the National Academy of Sciences of the United States of America.

Blog post

A. Carpineti, Physicists Take Particle Accelerator On 5,000-Kilometer Trip To Understand The Nature Of Muons. IFLScience (2017). Available at: https://www.iflscience.com/physics/physicists-take-particle-accelerator-on-5000kilometer-trip-to-understand-the-nature-of-muons/ [Accessed 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, “Airline Deregulation: Changes in Airfares, Service, and Safety at Small, Medium-Sized, and Large Communities” (U.S. Government Printing Office, 1996).

Theses and dissertations

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

Doctoral dissertation

A. Salifu, “Names that prick: Royal praise names in Dagbon, northern Ghana,” Indiana University, Bloomington, IN. (2008).

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

Photographs by GEORGE ETHEREDGE for THE NEW YORK TIMES, The Color Red. New York Times RE12 (2017).

In-text citations

References should be cited in the text by sequential numbers in parentheses:

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	Proceedings of the National Academy of Sciences of the United States of America
Abbreviation	Proc. Natl. Acad. Sci. U. S. A.
ISSN (print)	0027-8424
ISSN (online)	1091-6490
Scope	Multidisciplinary