Cofer, Michael (1960-2019) The Football Autograph Encyclopedia
1991 Pro Line Portraits #284 Michael Cofer - NM-MT
Former Lions All-Pro linebacker Mike Cofer dies at age 58
2011 NWCC Football Media Guide by NWCC_Rangers - Issuu
Pro Football Journal: March 2019
2019 NFL season - Wikipedia
Larry Schmitt, Author at Big Blue Interactive
Pro Football Journal: March 2019
New York Giants History - Big Blue Interactive