APA (7th ed.) Citation

Duffy, B., & Duffy, C. (2019). Duffy (Second edition, revised and extended.). AAC Art Books Ltd..

Chicago Style (17th ed.) Citation

Duffy, Brian, and Chris Duffy. Duffy. Second edition, revised and extended. Woodbridge, Suffolk, UK: AAC Art Books Ltd., 2019.

MLA (9th ed.) Citation

Duffy, Brian, and Chris Duffy. Duffy. Second edition, revised and extended. AAC Art Books Ltd., 2019.