Lawvere, F. W., & Schanuel, S. H. (2009). Conceptual Mathematics: A First Introduction to Categories (2nd ed.). Cambridge University Press.
@book{lawvere-schanuel:2009,
  author = {Lawvere, F. William and Schanuel, Stephen H.},
  address = {New York, NY, USA},
  publisher = {Cambridge University Press},
  year = {2009},
  edition = {2nd},
  isbn = {0-521-89485-9},
  title = {Conceptual Mathematics: A First Introduction to Categories}
}