Panbiblion Principia mathematica, vol. 1 (of 3) Whitehead, Alfred North and Russell, Bertrand Principia mathematica, vol. 1 (of 3) / FOOTNOTES: FOOTNOTES: Project Gutenberg EPUB3 edition Whitehead, Alfred North and Russell, Bertrand Source notes Open passage Copy text Copy link [55] Cf. *14, above.
