Citation File Format (CFF)
Citation File Format is a human- and machine-readable file format in YAML 1.2 which provides citation metadata for software. It is maintained openly on GitHub: https://github.com/citation-file-format/citation-file-format.
The spectrum of available concepts for software citation metadata files reaches
CITATION files as suggested by Robin
Wilson  to full transitive credit encoded in JSON-LD
Along this spectrum, Citation File Format is located somewhere between these two extremes as it adds
machine-readability and thus a greater re-use potential to
but does not offer transitive credit capabilities (yet), or support for all
citation use cases as outlined by Smith et al. .
Citation File Format aims at providing a practical solution, and human-friendly properties such as readability and writability, for the most common software citation use cases, i.e., 1. Use software for a paper, 2. Use software in/with new software, and 15. Store software entry (cf. Table 2, , p. 6).
The basic structure of Citation File Format (i.e., having a message and one or more
references) explicitly reflects the structure of plain-text
and manifests its status as a compromise between what is currently useful and
usable, and what is desired (fully transitive credit and attribution). As such, it has value both as a discrete format with everyday application and as a input format populating other citation formats.
Software citations enhance the dissemination of code, improve software sustainability and ensure authors receive credit for development work. The Citation File Format is an indirect outcome of the discussion group “DS3. Development and implementation of a standard format for CITATION files.” at the Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE5.1) (6 September 2017, Manchester, UK). The group discussed the potential and outlined requirements for a format for machine-readable CITATION files, and has authored a blog post on the subject, published on the blog of the Software Sustainability Institute.
Members of the group were:
- Stephan Druskat (Humboldt-Universität zu Berlin, Germany), Lead
- Neil Chue Hong (Software Sustainability Institute, University of Edinburgh, UK)
- Raniere Silva (Software Sustainability Institute, University of Manchester, UK)
- Radovan Bast (University of Tromsø, Norway)
- Andrew Rowley (University of Manchester, UK)
- Alexander Konovalov (University of St. Andrews, UK)
One requirement for the blog post was to be able to make a concrete suggestion for a format for these machine-readable CITATION files, which triggered the development of Citation File Format.
Older versions for CFF are listed in the following table.
|1.0.3||Core module: PDF||1.0.3-1||10.5281/zenodo.3515946|
|1.0.2||Core module: PDF||1.0.2||10.5281/zenodo.1120256|
|1.0.1||Core module: PDF||1.0.1||10.5281/zenodo.1117789|
|1.0.0||Core module: PDF||-||10.5281/zenodo.1108269|
Contributions to CFF are welcome! Please have a look at the guidelines for contributing.
 R. Wilson, “Encouraging citation of software–introducing CITATION files.” 2013 [Online]. Available: https://goo.gl/7gZuSY
 D. S. Katz and A. M. Smith, “Transitive Credit and JSON-LD,” Journal of Open Research Software, vol. 3, no. 1, p. e7, Nov. 2015.
 A. M. Smith, D. S. Katz, K. E. Niemeyer, and FORCE11 Software Citation Working Group, “Software citation principles,” PeerJ Comput. Sci., vol. 2, no. e86, 2016 [Online]. Available: https://doi.org/10.7717/peerj-cs.86