APA (7th ed.) Citation

EPSTEIN. (1993). How to be happier day by day. Viking.

Chicago Style (17th ed.) Citation

EPSTEIN. How to Be Happier Day by Day. New York: Viking, 1993.

MLA (9th ed.) Citation

EPSTEIN. How to Be Happier Day by Day. Viking, 1993.

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