Levi, L. (1981). Preventing work stress. Addison-Wesley.
Lua i Stíl Chicago (17ú heag.)Levi, Lennart. Preventing Work Stress. Reading, Mass: Addison-Wesley, 1981.
Lua MLA (9ú heag.)Levi, Lennart. Preventing Work Stress. Addison-Wesley, 1981.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.