Etzel, M. J. (1997). Marketing. New York, NY: McGraw Hill.
Chicago Style aipamenaEtzel, Michael J. Marketing. New York, NY: McGraw Hill, 1997.
MLA aipamenaEtzel, Michael J. Marketing. New York, NY: McGraw Hill, 1997.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.