New York, 28 February 1974 - Institutional correspondence A letter from the Guerrilla Art Action Group to Richard Oldenburg
New York, 10 February 1956 - Institutional correspondence A letter from Louise A. Boyer to Petro (Nelly) Van Doesburg
New York, 5 March 1974 - Institutional correspondence Letter-poem by the Guerrilla Art Action Group send to Franco
