@InCollection{Matkowski:2002,
  author    = "J. Matkowski",
  title     = "On invariant generalized Beckenbach-Gini means",
  pages     = "219--230",
  year      = "2002",
  booktitle = "Functional equations - resilts and advances, ISBN: 1402004850",
  publisher = "Kluwer Academic Publishers",
  address   = "Dordrecht",
  series    = "Advances in Mathematics : 3",
}