Columbia subject headings:
Harvard subject headings:
Communists--Germany--Biography
Plättner, Karl, 1893-1945.
Plättner, Karl.
Radicalism--Germany
Revolutionaries--Germany--Biography
Revolutionaries--Germany.
Princeton subject headings:
Communists--Germany--Biography.
Plättner, Karl.
Radicalism--Germany.
Revolutionaries--Germany.