CiteProc-PUB is a wrapper for CSL deployment in the institutional repository PUB -- Publikationen an der Universität Bielefeld.
It reuses citeproc-php, a PHP implementation of the CSL citation formatting language designed by Bruce D'Arcus (Miami University, Ohio, USA) from Ron Jerome.
Due to local needs, CiteProc-PUB works with a local copy and a subset of the CSL styles available.
https://github.com/citation-style-language/styles