Lieberman, L. (1992). Preparation for the CLEP, College-Level Examination Program: The 5 general examinations (3rd ed.). Arco : Prentice Hall.
Chicago-viite (17. p.)Lieberman, Leo. Preparation for the CLEP, College-Level Examination Program: The 5 General Examinations. 3rd ed. New York: Arco : Prentice Hall, 1992.
MLA-viite (9. p.)Lieberman, Leo. Preparation for the CLEP, College-Level Examination Program: The 5 General Examinations. 3rd ed. Arco : Prentice Hall, 1992.
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