BOYD HARPER W. (1990). MARKETING RESEARCH: TEXT & CASES (7TH.). IRWIN MCGRAW-HILL.
Lua i Stíl Chicago (17ú heag.)BOYD HARPER W. MARKETING RESEARCH: TEXT & CASES. 7TH. HOMEWOOD: IRWIN MCGRAW-HILL, 1990.
Lua MLA (9ú heag.)BOYD HARPER W. MARKETING RESEARCH: TEXT & CASES. 7TH. IRWIN MCGRAW-HILL, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.