Columbia subject headings:
Neutrality--Spain--History--20th century.
Spain--Foreign relations--20th century.
Spain--Politics and government--1886-1931.
World War, 1914-1918--Spain.
Harvard subject headings:
Neutrality--Spain--History--20th century.
Spain--Foreign relations--20th century.
Spain--Politics and government--1886-1931.
World War, 1914-1918--Spain
Princeton subject headings:
Neutrality--Spain--History--20th century.
Spain--Foreign relations--20th century.
Spain--Politics and government--1886-1931.
World War, 1914-1918--Spain.