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
30 May 1996 - Newspapers The Spanish Government and the PNV (Basque Nationalist Party) discuss the transfer of Guernica