Columbia subject headings:
Authors, Spanish--20th century--Correspondence.
Machado, Antonio, 1875-1939--Correspondence.
Valderrama, Pilar de--Correspondence.
Harvard subject headings:
Authors, Spanish--20th century--Correspondence
Machado, Antonio, 1875-1939--Correspondence.
Valderrama, Pilar de.--Correspondence.
Princeton subject headings:
Authors, Spanish--20th century--Correspondence.
Machado, Antonio, 1875-1939. Correspondence.
Valderrama, Pilar de--Correspondence.