Kreitner, R. &. O. (1990). Business. Houghton.
Lua i Stíl Chicago (17ú heag.)Kreitner, Robert & Others. Business. Houghton, 1990.
Lua MLA (9ú heag.)Kreitner, Robert & Others. Business. Houghton, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.