APA (7th ed.) Citation

Horacek, P. (2007). Butterfly, butterfly. Walker Books Ltd.

Chicago Style (17th ed.) Citation

Horacek, Petr. Butterfly, Butterfly. London: Walker Books Ltd, 2007.

MLA (9th ed.) Citation

Horacek, Petr. Butterfly, Butterfly. Walker Books Ltd, 2007.

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