Cita APA (7th ed.)
Gamow, G., & Schwarz, A. (1969). Erde, unser Planet: A Planet called earth [Deutsch]. Ehrenwirth.
Cita Chicago (17th ed.)
Gamow, George, i Ana Schwarz. Erde, Unser Planet: A Planet Called Earth [Deutsch]. München: Ehrenwirth, 1969.
Cita MLA (9th ed.)
Gamow, George, i Ana Schwarz. Erde, Unser Planet: A Planet Called Earth [Deutsch]. Ehrenwirth, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.