Gorle Peter & James Long. (1973). Essentials of product planning. McGraw hill.
Chicago Edition CitationGorle Peter i James Long. Essentials of Product Planning. London: McGraw hill, 1973.
Cita MLAGorle Peter i James Long. Essentials of Product Planning. McGraw hill, 1973.
Atenció: Aquestes cites poden no estar 100% correctes.