Cita APA (7th ed.)

Hawking, S. W., & Penrose, R. (1996). The nature of space and time. Princeton University Press, ; Oxford University Press.

Cita Chicago (17th ed.)

Hawking, S. W., i Roger Penrose. The Nature of Space and Time. Princeton, N.J. : New York ; New Delhi: Princeton University Press, ; Oxford University Press, 1996.

Cita MLA (8th ed.)

Hawking, S. W., i Roger Penrose. The Nature of Space and Time. Princeton University Press, ; Oxford University Press, 1996.

Atenció: Aquestes cites poden no estar 100% correctes.