Columbia subject headings:
Engels, Friedrich, 1820-1895--Dictionaries.
Marx, Karl, 1818-1883--Dictionaries.
Harvard subject headings:
Engels, Friedrich, 1820-1895--Dictionaries.
Engels, Friedrich, 1820-1895--Indexes.
Marx, Karl, 1818-1883--Dictionaries.
Marx, Karl, 1818-1883--Indexes.
Princeton subject headings: