Nickels, W. G., McHugh, J. M., & McHugh, S. M. (1993). Understanding business (3rd edition.). Irwin.
Lua i Stíl Chicago (17ú heag.)Nickels, William G., James M. McHugh, agus Susan M. McHugh. Understanding Business. 3rd edition. Homewood, IL: Irwin, 1993.
Lua MLA (8ú heag.)Nickels, William G., et al. Understanding Business. 3rd edition. Irwin, 1993.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.