APA (7th ed.) Citation

Boulenger, E. G. (1925). The aquarium book. Duckworth.

Chicago Style (17th ed.) Citation

Boulenger, E. G. The Aquarium Book. London: Duckworth, 1925.

MLA (9th ed.) Citation

Boulenger, E. G. The Aquarium Book. Duckworth, 1925.