New York, 6 May 1955 - Institutional correspondence A letter from W.R. Keating & Company International to R. Lerondelle
New York, 23 January 1957 - Transport documents A letter from the vice-president of W. R. Keating & Company to Willem Sandberg
22 November 1980 - Institutional correspondence Rafael Fernández Quintanilla's letter to Javier Tusell, dated 22 November 1980