APA (7th ed.) Citation

Whitehead, A. N. (1927). Principia mathematica: To 56. C.U.Pr.

Chicago Style (17th ed.) Citation

Whitehead, Alfred North. Principia Mathematica: To 56. Cambridge: C.U.Pr, 1927.

MLA (9th ed.) Citation

Whitehead, Alfred North. Principia Mathematica: To 56. C.U.Pr, 1927.