Verderber, R. (2008). The challenge of effective speaking (Fourteenth edition.). Belmont, CA: Cengage Learning.
استشهاد بنمط شيكاغوVerderber, Rudolph. The Challenge of Effective Speaking. Fourteenth edition. Belmont, CA: Cengage Learning, 2008.
MLA استشهادVerderber, Rudolph. The Challenge of Effective Speaking. Fourteenth edition. Belmont, CA: Cengage Learning, 2008.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.