Bantam
Wikipedia: https://en.wikipedia.org/wiki/Bantam_Books
Ad, PW, July 28, 1945, at [24] (full-page ad announcing Bantam Books).
Ad, PW, Dec. 1, 1945, at [1-7] (pull-out ad showcasing the new series, including the first 20 titles to be published).
Ian Ballantine, Best Sellers at a Quarter: Bantam Books' New Marketing Program, PW, July 9, 1949, at 131-134.
Clarence Peterson, THE BANTAM STORY: THIRTY YEARS OF PAPERBACK PUBLISHING (Bantam revised & updated ed. 1975).
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.