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
Exhibition, MoMA, New York, June 2, 1967 – February 13, 1968 - Photograph View of the exhibition Guernica: Studies and Postscripts