Nelsen, R. B. (1993). Proofs without words: Exercises in visual thinking. The Mathematical Association of America.
Chicago-referens (17:e uppl.)Nelsen, Roger B. Proofs Without Words: Exercises in Visual Thinking. Washington, DC: The Mathematical Association of America, 1993.
MLA-referens (9:e uppl.)Nelsen, Roger B. Proofs Without Words: Exercises in Visual Thinking. The Mathematical Association of America, 1993.
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