Columbia subject headings:
Harvard subject headings:
Estrada, Genaro, 1887-1937--Archives.
Mexico--Foreign relations--1910-1946--Sources.
Mexico--Foreign relations--Sources.
Spain--Politics and government--1931-1939--Sources.
Princeton subject headings:
Estrada, Genaro, 1887-1937--Correspondence.
Mexico--Foreign relations--1910-1946--Sources.
Mexico--Foreign relations--Spain--Sources.
Spain--Foreign relations--Mexico--Sources.