tiffin, j. (1965). Industrial psychology. Prentice-hall, inc..
Lua i Stíl Chicago (17ú heag.)tiffin, joseph. Industrial Psychology. london: Prentice-hall, inc., 1965.
Lua MLA (9ú heag.)tiffin, joseph. Industrial Psychology. Prentice-hall, inc., 1965.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.