Columbia subject headings:
Engels, Friedrich, 1820-1895.
Marx, Karl, 1818-1883.
Russia--History--1801-1917.
Working class--Political activity--Russia--History--19th century.
Harvard subject headings:
Engels, Friedrich, 1820-1895
Marx, Karl, 1818-1883
Russia--History--1801-1917.
Working class--Political activity--Russia--History--19th century.
Princeton subject headings:
Engels, Friedrich, 1820-1895.
Marx, Karl, 1818-1883.
Russia--History--1801-1917.
Working class--Political activity--Russia--History--19th century.