APA-referens (7:e uppl.)

Fleming, J. H., & Asplund, J. (2007). Human sigma: Managing the employee-customer encounter. Gallup Press.

Chicago-referens (17:e uppl.)

Fleming, John H., och Jim Asplund. Human Sigma: Managing the Employee-customer Encounter. New York: Gallup Press, 2007.

MLA-referens (9:e uppl.)

Fleming, John H., och Jim Asplund. Human Sigma: Managing the Employee-customer Encounter. Gallup Press, 2007.