APA (7th ed.) Citation

Hoyle, F., & Hoyle, G. (1971). Fifth planet. Penguin Books.

Chicago Style (17th ed.) Citation

Hoyle, Fred, and Geoffrey Hoyle. Fifth Planet. Harmondsworth: Penguin Books, 1971.

MLA (8th ed.) Citation

Hoyle, Fred, and Geoffrey Hoyle. Fifth Planet. Penguin Books, 1971.

Warning: These citations may not always be 100% accurate.