Sources for letters credit are The Marvel Comics Index (Olshevsky 1981), 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).
Professor X secretly replaced by Changeling through issue #43.
Letters from Robert Thuotte, Doug Nikkel, Lewis Flock, Jon Ray, Connie Sheehand, Richard Struempler, Ken Jensen.