Cita APA (7th ed.)

Fredrickson, B. (2009). Positivity (First edition.). Three Rivers Press.

Cita Chicago (17th ed.)

Fredrickson, Barbara. Positivity. First edition. New York: Three Rivers Press, 2009.

Cita MLA (9th ed.)

Fredrickson, Barbara. Positivity. First edition. Three Rivers Press, 2009.