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/).
Printed in black-and-white on inside front cover.
Bruce Wayne Jr. is referred to as Batman Jr. in this chapter only. Kal-El Jr. is never referred to as Superman Jr.
Kal-El Jr. and Bruce Wayne Jr. return in issue #157 (May 1966).
Letters from Ellen Paget, Jay Wind, Don Walker, Tom Adams, Johnny Stephenson, Robert O'Donnell, Michael Clark, and Alva Maxwell.
An "Editor's Round-Table" reprint.