Ireland,Norman J. (1987). Product differentiation and non-price competition. Basil Blackwell.
Chicago Style aipamenaIreland,Norman J. Product Differentiation and Non-price Competition. New York: Basil Blackwell, 1987.
MLA aipamenaIreland,Norman J. Product Differentiation and Non-price Competition. Basil Blackwell, 1987.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.