This issue has variants.
Letters page letter from Peter Sanderson.
in Classic X-Men (Marvel, 1986 series) #7 (March 1987)
in The Official Marvel Index to the X-Men (Marvel, 1987 series) #5 (March 1988)
in El Asombroso Hombre Araña Presenta (Novedades, 1988 series) #45 (Febrero 23 de 1989)
in Marvel Masterworks (Marvel, 1987 series) #11 ([November] 1989)
in L' Uomo Ragno (Edizioni Star Comics, 1987 series) #67 (28 Febbraio 1991)
in X-Men Classic (Marvel Italia, 1995 series) #2 (Novembre 1995)
in Essential X-Men (Marvel, 1996 series) #1 (1996)
in X-Men : l'intégrale (Panini France, 2003 series) #1975-1976 (décembre 2003)
in Marvel Masterworks: The Uncanny X-Men (Marvel, 2009 series) #1 (2011 [second printing])
in Marvel Gold. La Imposible Patrulla-X (Panini España, 2011 series) #1 - Segunda Génesis (Abril 2011)
in Classic X-Men (Marvel, 1986 series) #7 (March 1987)
in El Asombroso Hombre Araña Presenta (Novedades, 1988 series) #45 (Febrero 23 de 1989)
in L' Uomo Ragno (Edizioni Star Comics, 1987 series) #66 (15 Febbraio 1991) [pp. 3, 9], #67 (28 Febbraio 1991) [p. 17]
in Marvel Masterworks (Marvel, 1987 series) #11 ([November] 1989)
in L' Uomo Ragno (Edizioni Star Comics, 1987 series) #66 (15 Febbraio 1991), #67 (28 Febbraio 1991)
in X-Men Classic (Marvel Italia, 1995 series) #2 (Novembre 1995)
in Essential X-Men (Marvel, 1996 series) #1 (1996)
in X-Men : l'intégrale (Panini France, 2003 series) #1975-1976 (décembre 2003)
in Marvel Masterworks: The Uncanny X-Men (Marvel, 2009 series) #1 (2011 [second printing])
in Marvel Gold. La Imposible Patrulla-X (Panini España, 2011 series) #1 - Segunda Génesis (Abril 2011)Sources for identification of colorist are The Marvel Comics Index (Olshevsky 1981), The Official Marvel Index to the X-Men (Olshevsky 1988), The Official Marvel Index to the X-Men (Ward 1994), and Official Index to the Marvel Universe (Vandal et al. 2009). GCD’s previous colors credit was to Michele [sic] Wrightson.