Principia Mathematica

@book{principiamathematica-book1927,
   author = {Whitehead, Alfred North and Russell, Bertrand},
   isbn = {9780521067911},
   month = jan,
   publisher = {Cambridge University Press},
   title = {Principia Mathematica},
   url = {https://www.cambridge.org/it/academic/subjects/mathematics/logic-categories-and-sets/principia-mathematica?format=WX&isbn=9780521067911},
   year = 1927
}