Gardner, M. (1963). Martin Gardner's Sixth book of mathematical games from Scientific American (NA.). W.H. Freeman and Company.
Chicago-viite (17. p.)Gardner, Martin. Martin Gardner's Sixth Book of Mathematical Games from Scientific American. NA. San Francisco: W.H. Freeman and Company, 1963.
MLA-viite (9. p.)Gardner, Martin. Martin Gardner's Sixth Book of Mathematical Games from Scientific American. NA. W.H. Freeman and Company, 1963.
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