Citazione APA

Verderber, R., Sellnow, D. D., & Verderber, K. S. (2012). Speak. Wadsworth Cengage learning.

Stile di citazione Chicago

Verderber, Rudolph, Deanna D. Sellnow, e Kathleen S. Verderber. Speak. Boston: Wadsworth Cengage learning, 2012.

Citazione MLA

Verderber, Rudolph, et al. Speak. Wadsworth Cengage learning, 2012.