Ferber, R. (1949). Market research. McGraw Hill.
Chicago Style (17th ed.) ZitazioaFerber, Robert. Market Research. New York: McGraw Hill, 1949.
MLA (9th ed.) ZitazioaFerber, Robert. Market Research. McGraw Hill, 1949.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.