Columbia subject headings:
Harvard subject headings:
Harden, Maximilian, 1861-1927
Kautsky, Karl, 1854-1938.
World War, 1914-1918--Causes
Princeton subject headings:
Harden, Maximilian, 1861-1927.
Kautsky, Karl, 1854-1938.
World War, 1914-1918--Causes.