Pencils and inks credits verified by Jack Burnley. Letters credit from Todd Klein via his Klein Letters blog (18 September 2016, http://kleinletters.com/Blog/ira-schnapp-in-worlds-finest-comics-part-1/).
Inside front cover.
Inker identification by Bob Hughes.
Simon art credits confirmed via Harry Mendryk: https://kirbymuseum.org/blogs/simonandkirby/archives/2650
Kirby pencils per Harry Mendryk and the Jack Kirby Checklist. Swan pencils per Craig Delich. Inker identification made by Curt Swan to Craig Delich.
Letters credit from Todd Klein via his Klein Letters blog (19 September 2016, http://kleinletters.com/Blog/ira-schnapp-in-worlds-finest-comics-part-2/).
Letters credit from Todd Klein via his Klein Letters blog (19 September 2016, http://kleinletters.com/Blog/ira-schnapp-in-worlds-finest-comics-part-2/).
Writer identification by Bob Hughes. Mortimer signed his last name on street sign on Page 10, Panel 3. Letters credit from Todd Klein via his Klein Letters blog (19 September 2016, http://kleinletters.com/Blog/ira-schnapp-in-worlds-finest-comics-part-2/).