Meudon, 19 November 1955 - Institutional correspondence Nelly Van Doesburg's letter to Louise Boyer, dated 19 November 1955
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.
22 November 1980 - Institutional correspondence Rafael Fernández Quintanilla's letter to Javier Tusell, dated 22 November 1980
August-September 1990 - Institutional correspondence Correspondence on an exhibition project in Hiroshima