@article{Piątek:2001,
  author  = "K. Piątek and W. Leoński",
  title   = "Wehrl's entropy and a mesure of intermode correlations in phase space",
  journal = "Journal of Physics A : Mathematical and General",
  volume  = "Vol. 34",
  pages   = "4951--4967",
  year    = "2001",
}