@article{Maciejewski:2002,
  author  = "A. Maciejewski and A. Nowicki",
  title   = "Algebras of constants for some extensions of derivations",
  journal = "Indagationes Mathematicae - New Series",
  volume  = "Vol. 13",
  number  = "no 1",
  pages   = "77--88",
  year    = "2002",
}