On-sale date from ad in Superman's Pal, Jimmy Olsen #81 and copyright registration.
Continues the trend of no Robin on the cover.
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. Also appears in December 1960 issues.
Contains letter from Frank Brunner.