Win Mortimer verified pencils and inks credits to Craig Delich. 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/).
Writer identification by Bob Hughes. 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/).
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 per Martin O'Hearn, but is not listed in Otto Binder's 1963/1964 listing of his DC credits.
writer credit by Bob Hughes
Writer identification by Bob Hughes. 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/).
Inker credit by Bob Hughes. This ad showed up in all DC titles this month, and the inks have been alternately credited to Win Mortimer or Stan Kaye.