APA (7th ed.) Citation

(2015). O's little book of happiness (First edition.). Flatiron Books.

Chicago Style (17th ed.) Citation

O's Little Book of Happiness. First edition. New York: Flatiron Books, 2015.

MLA (8th ed.) Citation

O's Little Book of Happiness. First edition. Flatiron Books, 2015.

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