APA (7th ed.) Citation

Butterworth, B. Oliver octopus. Ladybird Books.

Chicago Style (17th ed.) Citation

Butterworth, Ben. Oliver Octopus. United Kingdom: Ladybird Books.

MLA (9th ed.) Citation

Butterworth, Ben. Oliver Octopus. Ladybird Books.

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