Cita APA (7th ed.)

Hoyle, F., & Holey, G. (1963). Fifth planet. Penguin Books.

Cita Chicago (17th ed.)

Hoyle, Fred, i Geoffrey Holey. Fifth Planet. Harmondsworth: Penguin Books, 1963.

Cita MLA (9th ed.)

Hoyle, Fred, i Geoffrey Holey. Fifth Planet. Penguin Books, 1963.