@article{Kowalewska-Kudłaszyk:2006,
  author  = "A. Kowalewska-Kudłaszyk and J. Kalaga and W. Leoński",
  title   = "Quantum nonlinear oscillator, chaos and Wigner function",
  journal = "Acta Physica Hungarica B : Quantum Electronics",
  volume  = "Vol. 26",
  number  = "no 3-4",
  pages   = "243--246",
  year    = "2006",
}