Sources for letters credit are The Marvel Comics Index (Olshevsky 1981), The Official Marvel Index to the X-Men (Olshevsky 1987), and The Official Marvel Index to the X-Men (Ward 1994).
Marie Severin's credit per Feran Delgado's site, which features a stat of the original artwork
: http://ferrandelgado.blogspot.com/search?updated-max=2012-04-22T08:25:00%2…
Red Raven (last app. in RED RAVEN #1; last chron. app. in INVADERS #38; next app. in SUB-MARINER #26)
Sources for particularization of writing credits are The Official Marvel Index to the X-Men (Olshevsky 1987), The Official Marvel Index to the X-Men (Ward 1994), and Official Index to the Marvel Universe (Vandal et al. 2009). Sources for particularization of pencils credits are The Official Marvel Index to the X-Men (1987) and The Official Marvel Index to the X-Men (1994).
Letters from Keith Giffen (future comics artist), Greg Feeley, Joel Richter, Carl Gafford, Scott Douglas, David Craven, David Bradstreet and Grady Richardson.