APA

Popham E. L., Schrag A. F. & Blockhus W. (1975). A teaching-learning system for business education. New York: Gregg Division, McGraw-Hill.

Chicago

Popham Estelle L, Schrag Adele Frisbie and Blockhus Wanda. 1975. A teaching-learning system for business education. New York: Gregg Division, McGraw-Hill.

Harvard

Popham E. L., Schrag A. F. and Blockhus W. (1975). A teaching-learning system for business education. New York: Gregg Division, McGraw-Hill.

MLA

Popham Estelle L, Schrag Adele Frisbie and Blockhus Wanda. A teaching-learning system for business education. New York: Gregg Division, McGraw-Hill. 1975.