Disputed penciler credit--Jack Kirby (layouts) Werner Roth (pencils) per Rich Donnelly, Steve Whitaker, and Bob Ford. Bob Ford asserts that someone other than Jack Kirby or Dick Ayers modified Magneto's face. Nick Caputo believes that the Magneto figure was pencilled by Kirby and the rest of the cover by Roth (GCD Error List 29 March 2007). Sol Brodsky inking credit added per Nick Caputo, Jan 1, 2011. Credits from print indexes vary. The Official Marvel Index to the X-Men (Olshevsky 1987) attributed pencils to Roth, inks to Ayers. The Official Marvel Index to the X-Men (Ward 1994) attributed layouts to Kirby, pencils to Roth, inks to Ayers. Official Index to the Marvel Universe (Vandal et al. 2009) attributed pencils to Kirby.
Sources for letters credit are The Official Marvel Index to the X-Men (1987), The Official Marvel Index to the X-Men (1994), and Official Index to the Marvel Universe.