Richard Stallman -- original version and continuing revisions of
  regex.c and regex.h, and original version of the documentation.

Karl Berry and Kathryn Hargreaves -- extensive modifications to above,
  and all test files.

Jim Blandy -- original version of re_set_registers, revisions to regex.c.

Joe Arceneaux, David MacKenzie, Mike Haertel, Charles Hannum, and
probably others -- revisions to regex.c.