Herr, E. L. (1988). Career guidance through the life span: Systematic approaches (3rd ed.). Little, Brown and Co..
Lua i Stíl Chicago (17ú heag.)Herr, Edwin L. Career Guidance Through the Life Span: Systematic Approaches. 3rd ed. Boston: Little, Brown and Co., 1988.
Lua MLA (9ú heag.)Herr, Edwin L. Career Guidance Through the Life Span: Systematic Approaches. 3rd ed. Little, Brown and Co., 1988.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.