FERPER, R. (1974). Handbook Of Marketing Research Robert Ferper. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)FERPER, Robert. Handbook Of Marketing Research Robert Ferper. McGraw-Hill, 1974.
Lua MLA (8ú heag.)FERPER, Robert. Handbook Of Marketing Research Robert Ferper. McGraw-Hill, 1974.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.