Kirby's co-plot credit is widely acknowledged by Lee and Kirby in numerous interviews. Credit here reads: "Created and Choreographed by: Stan (The Man) Lee and Jack (King) Kirby."
Letters from Lamar Blaylock, George Ferguson, Evan Katten, Gary Dahlberg, Tom Zmudzinski, Bruce Coville, and Mike Esterson; includes Know Ye These, the Hallowed Ranks of Marveldom.