Columbia subject headings:
Engels, Friedrich, 1820-1895.
Marx, Karl, 1818-1883.
Harvard subject headings:
Communists--Biography
Engels, Friedrich, 1820-1895
Engels, Friedrich, 1820-1895--Bibliography.
Engels, Friedrich, 1820-1895--Chronology.
Engels, Friedrich, 1820-1895--Language--Glossaries, vocabularies, etc.
Marx, Karl, 1818-1883
Marx, Karl, 1818-1883--Bibliography.
Marx, Karl, 1818-1883--Chronology.
Marx, Karl, 1818-1883--Language--Glossaries, vocabularies, etc.
Princeton subject headings:
Engels, Friedrich, 1820-1895.
Marx, Karl, 1818-1883.