George Lichtheim. (1971). Imperialism. Penguin.
Cita Chicago (17th ed.)George Lichtheim. Imperialism. Harmondsworth: Penguin, 1971.
Cita MLA (9th ed.)George Lichtheim. Imperialism. Penguin, 1971.
Atenció: Aquestes cites poden no estar 100% correctes.