latex reference style

(Note that author-date styles arose because the simple and clear citation style that plain produces is so awkward in a traditional manuscript preparation scenario. However, TeX-based document production does away with all those difficulties, leaving us free once again to use the simple option.)
Fortunately, help is at hand, on the Web, with this problem:

The package provides an implementation of the bibliography styles of both the AIP and the APS for Bib L a T e X . This implementation follows standard Bib L a T e X conventions, and can be used simply by loading Bib L a T e X with the appropriate option:
A demonstration database is provided to show how to format input for the style. Style options are provided to cover the minor formatting variations between the AIP and APS bibliography styles.

amsrefs is included on TeX Live and other distributions from 2009 or later. If you don’t have such a distribution installed, use the following instructions.
amsrefs is an extension package for LaTeX that has the following features:

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B) Hand coding entries into your BibTeX database. Not recommended but sometimes unavoidable, especially for unindexed literature or other uncommon resource types.
Most of the commonly used reference/citation managers (EndNote, Zotero, Mendeley, etc.) will have an option to export to a BibTeX database. It is highly recommended that you use one. Citation libraries can also be exported from one manager to another if you want to try different software.

Reference style can be: plain, unsrt, alpha, abbrv, ieeetr, acm, siam, apalike, amsplain, abstract, agsm

• How to cite your reference?

title = instein equations>
Information about the preferred format for the individual journals can be found in the specific journal’s Instructions for Authors.

The PNAS SI appendix template can be accessed here: PNAS SI Appendix Template.
PNAS provides formatted templates for research reports, Brief Reports, SI Appendix files, and single-column mathematics papers on Overleaf. Authors may prepare their manuscript on the Overleaf site and download a compiled PDF for initial submission. When submitting publication-ready files at revision, a .zip file containing all necessary source files can be downloaded from Overleaf. When uploaded to the submission site, the files will be unzipped and automatically classified by file type. While we encourage authors to use Overleaf in order to reduce compilation errors in submission, the template files can also be downloaded and used with your preferred TeX distribution.

• One standard statistical style is the ASA style. You’ll need style files bst and sty that implement this.
• Another style is Natbib.