Roxbury, 22 November 1955 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 22 November 1955
Roxbury, 12 January 1956 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 12 January 1956
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