@book{spivak2019calculus,
  title={Calculus},
  author={Spivak, M. and Sala, J.M.O. and Cam{\'o}, L.S.},
  isbn={9788429194807},
  url={https://books.google.com.mx/books?id=HxxFyQEACAAJ},
  year={2019},
  publisher={Reverte}
}