Cita APA (7a ed.)

Emmons, R. A., & McCullough, M. E. (2004). The psychology of gratitude. University Press.

Cita Chicago Style (17a ed.)

Emmons, Robert A., y Michael E. McCullough. The Psychology of Gratitude. Oxford: University Press, 2004.

Cita MLA (9a ed.)

Emmons, Robert A., y Michael E. McCullough. The Psychology of Gratitude. University Press, 2004.