Cita APA (7a ed.)
Hawking, S. W., & Penrose, R. (2010). The nature of space and time (13th print.). Princeton University Press.
Cita Chicago Style (17a ed.)
Hawking, S. W., y Roger Penrose. The Nature of Space and Time. 13th print. Princeton, N.J.: Princeton University Press, 2010.
Cita MLA (9a ed.)
Hawking, S. W., y Roger Penrose. The Nature of Space and Time. 13th print. Princeton University Press, 2010.
Precaución: Estas citas no son 100% exactas.