Whitehead, A. N., & Russell, B. (1927). Principia mathematica. V. 1.- 2nd ed. University Press.
Dyfyniad Arddull ChicagoWhitehead, Alfred North, and Bertrand Russell. Principia Mathematica. V. 1.- 2nd Ed. Cambridge: University Press, 1927.
Dyfyniad MLAWhitehead, Alfred North, and Bertrand Russell. Principia Mathematica. V. 1.- 2nd Ed. University Press, 1927.
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