Barrow, J. D. (1992). Pi in the sky: Counting, thinking, and being (First edition. pbk. edition.). Little Brown and Company.
Lua i Stíl Chicago (17ú heag.)Barrow, John D. Pi in the Sky: Counting, Thinking, and Being. First edition. pbk. edition. Boston: Little Brown and Company, 1992.
Lua MLA (9ú heag.)Barrow, John D. Pi in the Sky: Counting, Thinking, and Being. First edition. pbk. edition. Little Brown and Company, 1992.
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