Citazione APA

Stephen Hawking & Roger Penrose. (1998). The nature of space and time. Oxford University Press.

Stile di citazione Chicago

Stephen Hawking e Roger Penrose. The Nature of Space and Time. New Delhi: Oxford University Press, 1998.

Citazione MLA

Stephen Hawking e Roger Penrose. The Nature of Space and Time. Oxford University Press, 1998.