Meudon, 19 November 1955 - Institutional correspondence Nelly Van Doesburg's letter to Louise Boyer, dated 19 November 1955
New York, 6 May 1955 - Institutional correspondence A letter from W.R. Keating & Company International to R. Lerondelle
Meudon, 19 November 1955 - Institutional correspondence Nelly Van Doesburg's letter to Louise Boyer, dated 19 November 1955
Meudon, 29 December 1955 - Institutional correspondence Nelly Van Doesburg's letter to Louise Boyer, dated 29 December 1955
Meudon, 13 February 1956 - Institutional correspondence Petro (Nelly) Van Doesburg's letter Alfred H. Barr Jr.
New York, 23 January 1957 - Transport documents A letter from the vice-president of W. R. Keating & Company to Willem Sandberg