Gaya APA

Festinger, G, M, D, D, D. (2005). Essentials of research design and methodology . New Jersey: John Wiley & Sons, Inc.

Gaya MLA

Festinger, Geoffrey, Marczyk,, David, DeMatteo,, David. "Essentials of research design and methodology". New Jersey: John Wiley & Sons, Inc, 2005. Electronic Resource.