Principia mathematica,
by Alfred North Whitehead ... and Bertrand Russell.
APA Citation
Whitehead, A. North., Russell, B. (1910). Principia mathematica. Cambridge: University Press.
MLA Citation
Whitehead, Alfred North, 1861-1947, and Bertrand Russell. Principia Mathematica. Cambridge: University Press, 1910.
Warning: These citations may not always be complete (especially for serials).