Columbia subject headings:
Harvard subject headings:
Communism--History
Communists--Germany--Biography
Engels, Friedrich, 1820-1895
Labor movement--History
Marx, Karl, 1818-1883
Socialism--History
Princeton subject headings:
Communists--Germany--Biography.
Engels, Friedrich, 1820-1895--Friends and associates.
Engels, Friedrich, 1820-1895.
Marx, Karl, 1818-1883--Friends and associates.
Marx, Karl, 1818-1883.
Socialists--Germany--Biography.