Gaya APA

J., E., ESSEF, M, S. (1974). Developing instructional materials/ Peter J. Essef, Mary S. Essef . Columbia: ESF Press.

Gaya MLA

J., Essef,Peter., ESSEF, Mary, S.. "Developing instructional materials/ Peter J. Essef, Mary S. Essef". Columbia: ESF Press, 1974. Text.