Cita APA (7th ed.)

O'Brien, R. (1980). Machines (2nd ed.). Time-Life Books.

Cita Chicago (17th ed.)

O'Brien, Robert. Machines. 2nd ed. Hong Kong: Time-Life Books, 1980.

Cita MLA (9th ed.)

O'Brien, Robert. Machines. 2nd ed. Time-Life Books, 1980.