APA (7th ed.) Citation

Whitehead, A. N., & Russell, B. (1973). Principia mathematica (2nd ed., repr.). At the University Press.

Chicago Style (17th ed.) Citation

Whitehead, Alfred North, and Bertrand Russell. Principia Mathematica. 2nd ed., repr. Cambridge: At the University Press, 1973.

MLA (9th ed.) Citation

Whitehead, Alfred North, and Bertrand Russell. Principia Mathematica. 2nd ed., repr. At the University Press, 1973.