APA (7th ed.) Citation

Piggott, S. (1974). The Druids. Penguin Books.

Chicago Style (17th ed.) Citation

Piggott, Stuart. The Druids. Harmondsworth, Middlesex, Eng: Penguin Books, 1974.

MLA (9th ed.) Citation

Piggott, Stuart. The Druids. Penguin Books, 1974.