APA استشهاد

Gorle, P., & Long, J. (1973). Essentials of product planning. McGraw-Hill.

استشهاد بنمط شيكاغو

Gorle, Peter, و James Long. Essentials of Product Planning. London: McGraw-Hill, 1973.

MLA استشهاد

Gorle, Peter, و James Long. Essentials of Product Planning. McGraw-Hill, 1973.