Paris, 5 December 1955 - Institutional correspondence Maurice Lefebvre-Foinet's letter to Willem Sandberg
New York, 7 March 1956 - Institutional correspondence A telegram from Edgar Craig Schenk to Pablo Picasso
2 March 1974 - Institutional correspondence A letter from Karl Denim, S. S. Kush and Joshua Jericho in defence of Tony Shafrazi