Lieberman, L. (1992). Preparation for the CLEP, College-Level Examination Program: The 5 general examinations (3rd ed.). Arco : Prentice Hall.
Lua i Stíl Chicago (17ú heag.)Lieberman, Leo. Preparation for the CLEP, College-Level Examination Program: The 5 General Examinations. 3rd ed. New York: Arco : Prentice Hall, 1992.
Lua MLA (9ú heag.)Lieberman, Leo. Preparation for the CLEP, College-Level Examination Program: The 5 General Examinations. 3rd ed. Arco : Prentice Hall, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.