참고문헌
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- K. Hrbacek and T. Jech, Introduction to Set Theory, Marcel Dekker, INC. New York and Base, 1984.
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- E. Mendelson, Introduction to Mathematical Logic, D. Van Nostrand Co., New york, 1979.
- C. C. Pinter, Set Theory, Addison-Wesely, Reading, Massachcett, 1971.
- R. L. Vaught, Set Theory, BirkhaCer Boston Inc., Boston, 1985.