Columbia subject headings:
Harvard subject headings:
Costa y Martínez, Joaquín, 1846-1911
Spain--History--1868-1931.
Unamuno, Miguel de, 1864-1936
Princeton subject headings:
Costa y Martínez, Joaquín, 1846-1911.
Spain--Politics and government--1886-1931.
Spain--Social conditions.
Unamuno, Miguel de, 1864-1936.