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, 24 September 1957 - Institutional correspondence Virginia Pearson's letter to Alfred H. Barr Jr.
New York, 5 November 1957 - Institutional correspondence Virginia Pearson's letter to Katharine Kuh, dated 5 November 1957
New York, 20 September 1957 - Institutional correspondence Virginia Pearson's letter to Katharine Kuh, dated 20 September 1957