The Proceedings of the National Academy of Sciences of the United States of America (PNAS) allows authors to submit their manuscript formatted in LaTeX to the PNAS Journal. For this, they provide a template which contains the structure and reference style they would like for submissions.
The PNAS LaTeX template features a two-column layout and mirrors the layout seen in final publications released by PNAS. This allows authors to determine the exact length of their manuscripts as they will appear if accepted. The template is highly structured so each piece of information is clearly separated into sections for easy editing. PNAS requests that references are included manually within the template as ‘\bibitem’s rather than in a .bib file as usual, an example reference list is included with the template along with instructions on how to extract this reference list from your library of references. Tables and figures are included at the end of this template and are only used for in-text citation; separate high-resolution figure files must be submitted along with your manuscript for inclusion into the final article. PNAS have a useful guide for typesetting your article using this template which you can download here.
The PNAStwo class provided here was created and is owned by PNAS. It is an unmodified version of that found on the Submitting LaTeX Files section of the PNAS website. The template provided here is a modified version of the blank template found on the same page with the inclusion of example content to illustrate the use of the template and improved commenting throughout the template. The document structure and function remain identical to the PNAS template.