EqualityBib is a project mainly written in ..., it's free.
Bibliography of philosophical papers on equality
README
EqualityBib
Created by Mark Eli Kalderon 2010-09-22
A bibliography of relatively recent philosophical papers on equality compiled principally by Véronique Munoz-Dardé.
The bibliography will be maintained separately from Philosophy.bib, though it will be merged into Philosophy.bib.
The bibliography is a BibTeX file created using BibDesk.
See this blog post for the rationale for keeping a BibTeX file in an open Git repository.