Peter Schaffter observes in http://lists.gnu.org:443/archive/html/groff/2021-08/msg00019.html:

"Nowhere is there any indication what style of bibliographic formatting is provided by the ms/mm/me implementations of refer(1), a matter of some importance for authors preparing submissions and students writing papers.  Mom is upfront about formatting in MLA style, which is useful to groffers seeking a macro package that does MLA.  I believe the other packages should follow suit and state, in their manpage or in refer(1), which style guide is being followed for refer(1) bibliographies."