Watkins, D. E., & De Bower, H. F. (1927). Effective speech: Including mental training and the development of personality. New York: The De Bower Publishing.

Watkins, Dwight Everett, و Herbert Francis De Bower. Effective Speech: Including Mental Training and the Development of Personality. New York: The De Bower Publishing, 1927.

Watkins, Dwight Everett, و Herbert Francis De Bower. Effective Speech: Including Mental Training and the Development of Personality. New York: The De Bower Publishing, 1927.