Madrid, 2 December 1975 and Berkeley, California, 8 January 1976 - Institutional correspondence A letter from José Mario Armero to Herschel B. Chip, with reply
New York, 5 November 1938 - Institutional correspondence Herman F. Reissig's letter to Julius Perlstein
New York, 1 November 1939 - Institutional correspondence Herman F. Reissig's letter to Marcelene Peterson, dated 1 November 1939
New York, 2 November 1939 - Institutional correspondence Herman F. Reissig's letter to Milton Wichner
New York, 17 November 1939 - Institutional correspondence Herman F. Reissig's letter to Marcelene Peterson, dated 17 November 1939