In order to make software easily citable, a “citation file format” *.CITATION.cff should be included in the root of the repository.

cff-version: 1.0.3
message: If you use this software, please cite it as below.
authors:
  - family-names: Germann
    given-names: Christopher, Benjamin
    orcid: https://orcid.org/0000-0002-1573-4651
title: Psychology Meta Search Tool
version: 1.0.2
URL: https://christopher-germann.de/psychology-meta-search-tool-v1-02/
date-released: 2012-07-16

In R the citation of a given package can be extracted as follows (using BibTeX for LaTex).

 
citation('ggplot2')

#To cite ggplot2 in publications, please use:
#H. Wickham. ggplot2: elegant graphics for data analysis. Springer New York, 2009.
#A BibTeX entry for LaTeX users is

@Book{,
   author = {Hadley Wickham},
   title = {ggplot2: elegant graphics for data analysis},
   publisher = {Springer New York},
   year = {2009},
   isbn = {978-0-387-98140-6},
   url = {http://had.co.nz/ggplot2/book},
 }

GitHub

https://github.com/citation-file-format/citation-file-format/blob/master/CONTRIBUTING.md

References

Smith, Arfon M., Katz, Daniel S., Niemeyer, Kyle E., & FORCE11 Software Citation Working Group. (2016). Software citation principles. PeerJ Computer Science, 2, e86. https://doi.org/10.7717/peerj-cs.86.

Katz, Daniel S, & Smith, Arfon M. (2015). Implementing transitive credit with JSON-LD. Journal of Open Research Software, 3(e7). https://doi.org/10.5334/jors.by.