Citation File Format (CFF), a YAML 1.2-based format for providing citation metadata for (research/scientific) software.

• CFF github repo
• Guide to the CFF v1.2 schema, including such niceties as credit redirection
• One of many CFF file generators (here is a table of other tools).
• Making software citation easi(er) - The Citation File Format and its integrations, slides for a presentation by Stephan Druskat (one of the CFF maintainers).
• There are, of course, R-based CFF generators. cffr is backed by rOpenSci.
• Stephan Druskat's cfftracker answers the question: how many repos on Github contain CITATION.cff files? At the moment just north of 1000 repos (less than I thought, to be honest). Keep adding CFF to your scientific repos, people :-)

Via Martin Fenner (twice over).