Paris, 18 October 1948 - Institutional correspondence A letter from Mariano Miguel to José Ballester-Gozalvo
12 September 1981 - Newspapers Protests in the Basque Country over the installation of Guernica in the Casón del Buen Retiro
Mougins, 10 December 1970 - Personal correspondence A telegram Mariano Miguel, Picasso’s secretary, sent to Raimon Noguera to request the cancellation of the opening ceremony for the expansion of Museo Picasso