Gaya APA

Krueger, R, A., Casey, M, A. (2015). Focus groups : a practical guide for applied research / 5th edition (5th ed.). Thousand Oaks, California: SAGE Publications.

Gaya MLA

Krueger, Richard, A.., Casey, Mary, Anne. "Focus groups : a practical guide for applied research / 5th edition". 5th ed. Thousand Oaks, California: SAGE Publications, 2015. Text.