@article{Matkowski:2008,
  author  = "J. Matkowski and M. Wróbel",
  title   = "Locally defined operators in the space of Whitney differentiable functions",
  journal = "Nonlinear Analysis, Theory, Methods & Applications",
  volume  = "Vol. 68",
  number  = "no 10",
  pages   = "2933--2942",
  year    = "2008",
}