Wikipedia: https://en.wikipedia.org/wiki/Alfred_A._Knopf
Archives: Alfred A. Knopf, Inc. Records 1873-1996 (bulk 1945-1980), Harry Ransom Center, University of Texas-Austin, https://norman.hrc.utexas.edu/fasearch/findingAid.cfm?eadid=00301.
Gayle Feldman, The Borzoi Three-Quarterly, PW, Oct. 26, 1990, at 46-51 (profile of Knopf after 75 years).
Clare Swanson, A Century of Knopf, PW, May 18, 2015, at 10-11.
Rachel Deahl, Sonny Mehta: Person of the Year, PW, Dec. 7, 2015, at 22-24.
ALFRED A. KNOPF, 1915-2015: A CENTURY OF PUBLISHING (Knopf 2015)
Clare Swanson, A Century of Knopf, PW, May 18, 2015, at 10-11.