Cita APA (7a ed.)

Kaufmann, W. J. (1977). The cosmic frontiers of general relativity. Penguin Books.

Cita Chicago Style (17a ed.)

Kaufmann, William J. The Cosmic Frontiers of General Relativity. Middlesex: Penguin Books, 1977.

Cita MLA (9a ed.)

Kaufmann, William J. The Cosmic Frontiers of General Relativity. Penguin Books, 1977.