refer was written by Mike Lesk at Bell Laboratories[1][2] in or before 1978, and is now available as part of most Unix-like operating systems.
A free reimplementation exists as part of the groff package.
As of 2015[update], refer sees little use, primarily because troff itself is not used much for longer technical writing that might need software support for reference and citation management.
Within each record, each field starts with a %-sign at the beginning of the line and one character immediately after.
The conventional meaning of each field is shown in the table below.