APA (7th ed.) Citation

O'Brian, P. (2006). The Catalans. HarperCollinsPublishers.

Chicago Style (17th ed.) Citation

O'Brian, Patrick. The Catalans. London: HarperCollinsPublishers, 2006.

MLA (9th ed.) Citation

O'Brian, Patrick. The Catalans. HarperCollinsPublishers, 2006.

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