Airmail cover with 'Prof. Dr P. Busse Grawitz, Avenida 24 de Septiembre 1091, Cordoba' return address handstamp on reversefranked with 1935 5c orange brown, and 1936 40c purple & mauve and 1p light blue & chocolate (SG 653b, 658 & 660a) tied by two fine strikes of OF. POSTAL AMBULANTE E-131 cds dated 14 MAR 1939. Addressed to SWITZERLAND.