FERELL O C. (1993). MARKETING CONCEPTS AND STRATERGIES (8TH.). HOUGHTON & MIFFLIN.
Lua i Stíl Chicago (17ú heag.)FERELL O C. MARKETING CONCEPTS AND STRATERGIES. 8TH. BOSTON: HOUGHTON & MIFFLIN, 1993.
Lua MLA (9ú heag.)FERELL O C. MARKETING CONCEPTS AND STRATERGIES. 8TH. HOUGHTON & MIFFLIN, 1993.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.