New York, 16 October 1981 - Institutional correspondence John Koegel's letter to Javier Tusell, dated 16 October 1981
New York, 16 October 1981 - Institutional correspondence John Koegel's letter to Javier Tusell, dated 16 October 1981
New York, 16 October 1981 - Institutional correspondence John Koegel's letter to Javier Tusell, dated 16 October 1981
30 October 1981 - Institutional correspondence John Koegel's letter to Richard E. Oldenburg, dated 30 October 1981
Madrid, 29 May and 10 June 1981 - Institutional correspondence A letter from Felipe Cons Gorostola to Álvaro Martínez Novillo, and reply
New York, 31 August 1981 - Institutional correspondence John Koegel's letter to Richard E. Oldenburg, dated 31 August 1981