Liebert, R. M., & Spiegler, M. D. (1990). Personality: Strategies and issues (6th ed.). Brooks/Cole.
Lua i Stíl Chicago (17ú heag.)Liebert, Robert M., agus Michael D. Spiegler. Personality: Strategies and Issues. 6th ed. Pacific Grove, Calif: Brooks/Cole, 1990.
Lua MLA (9ú heag.)Liebert, Robert M., agus Michael D. Spiegler. Personality: Strategies and Issues. 6th ed. Brooks/Cole, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.