APA (7th ed.) Citation

Hefferon, K., & Lomas, T. (2015). Positive psychology. SAGE Reference.

Chicago Style (17th ed.) Citation

Hefferon, Kate, and Tim Lomas. Positive Psychology. Los Angeles: SAGE Reference, 2015.

MLA (9th ed.) Citation

Hefferon, Kate, and Tim Lomas. Positive Psychology. SAGE Reference, 2015.