in The X-Men Omnibus (Marvel, 2009 series) #1 ([April] 2009)
in Fantastic! (IPC, 1967 series) #8 (8 April 1967) [cover]
in Amazing Adventures (Marvel, 1979 series) #10 (September 1980)
in The Official Marvel Index to the X-Men (Marvel, 1987 series) #1 (May 1987)
in Marvel Masterworks (Marvel, 1987 series) #3 ([November] 1987)
in Uncanny X-Men Masterworks (Marvel, 1993 series) #1 (February 1993)
in Marvel Masterworks: The X-Men (Marvel, 1998 series) #[1] (December 1998)
in Essential Uncanny X-Men (Marvel, 1999 series) #1 (September 1999)
in Marvel Masterworks: The X-Men (Marvel, 2002 series) #1 (April 2002)
in X-Men No. 5 [Marvel Legends Reprint] (Marvel, 2005 series) #[nn] (May 2005) [cover]
in The X-Men Omnibus (Marvel, 2009 series) #1 ([April] 2009)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).
in Fantastic! (IPC, 1967 series) #7 (1 April 1967) [Black and white, pages 1-12 only.], #8 (8 April 1967) [Black and white, pages 13-24 only. ]
in Marvel Super-Heroes (Marvel, 1967 series) #24 (January 1970)
in Amazing Adventures (Marvel, 1979 series) #9 (August 1980) [pp 1-13], #10 (September 1980) [pp. 14-24]
in Marvel Masterworks (Marvel, 1987 series) #3 ([November] 1987)
in Uncanny X-Men Masterworks (Marvel, 1993 series) #1 (February 1993)
in X-Men: The Early Years (Marvel, 1994 series) #5 (September 1994)
in Marvel Special (Marvel Italia, 1994 series) #4 (Luglio 1995)
in Marvel Masterworks: The X-Men (Marvel, 1998 series) #[1] (December 1998)
in Essential Uncanny X-Men (Marvel, 1999 series) #1 (September 1999)
in Marvel Masterworks: The X-Men (Marvel, 2002 series) #1 (April 2002)
in X-Men No. 5 [Marvel Legends Reprint] (Marvel, 2005 series) #[nn] (May 2005)
in The X-Men Omnibus (Marvel, 2009 series) #1 ([April] 2009)