On sale date as listed in the Catalog of Copyright Entries, Periodicals, July-December 1960, page 361, registration number B847920.
Craig Delich and Pat Lang contend that Sheldon Moldoff was the inker. 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/).
Bob Klein and Gene Reed say Charles Paris inks.
Public service announcement that ran in the July 1960 (cover dates September and October) issues of DC Comics.