@inbook{7180,
  author = {Randall Shirts and William Reinhardt},
  title = {Formal Integrals for a Nonintegrable Dynamical System: Preliminary Report},
  year = {1981},
  pages = {277-287},
  publisher = {Springer US},
  address = {Boston, MA},
  isbn = {978-1-4613-3260-2},
  doi = {10.1007/978-1-4613-3258-9_21},
}