@article{Matkowski:1972,
  author  = "J. Matkowski",
  title   = "The uniqueness of solutions of a system of functional equations in some classes of functions",
  journal = "Aequationes Mathematicae",
  volume  = "Vol. 8",
  number  = "no 3",
  pages   = "233--237",
  year    = "1972",
}