Columbia subject headings:
International Socialist Congress.
Kautsky, Karl, 1854-1938.
Socialists--Germany--Biography.
Harvard subject headings:
Kautsky, Karl, 1854-1938.
Socialism--Germany
Socialist International (1889-1922)
Princeton subject headings:
Kautsky, Karl, 1854-1938.
Socialist International (1889-1922)
Socialists--Germany--Biography.