APA (7th ed.) Citation

Gibbs, P. E. (1977). British sipunculans: Keys and notes for the identification of the species. Academic Press.

Chicago Style (17th ed.) Citation

Gibbs, P. E. British Sipunculans: Keys and Notes for the Identification of the Species. London [etc.]: Academic Press, 1977.

MLA (9th ed.) Citation

Gibbs, P. E. British Sipunculans: Keys and Notes for the Identification of the Species. Academic Press, 1977.