APA

Porterfield J. D., . (1985). Selling on the phone. New York: Wiley Press.

Chicago

Porterfield James D, . 1985. Selling on the phone. New York: Wiley Press.

Harvard

Porterfield J. D., . (1985). Selling on the phone. New York: Wiley Press.

MLA

Porterfield James D, . Selling on the phone. New York: Wiley Press. 1985.