Penguin (US)

Wikipedia: https://en.wikipedia.org/wiki/New_American_Library

Penguin Books Plans Big Expansion Plan, PW, Sept. 15, 1945, at 1084-1086.

Ian and Betty Ballantine Books and Business Records, 1935-1994, bulk 1945-1973, Columbia University, Rare Book & Manuscript Library, https://findingaids.library.columbia.edu/ead/nnc-rb/ldpd_13511438.