@article{Kahlig:1996,
  author  = "P. Kahlig and A. Matkowska and J. Matkowski",
  title   = "On a class of composite functional equations in a single variable",
  journal = "Aequationes Mathematicae",
  volume  = "Vol. 52",
  number  = "no 3",
  pages   = "260--283",
  year    = "1996",
}