@article{Kahlig:1996,
  author  = "P. Kahlig and J. Matkowski",
  title   = "Functional equations involving the logarithmic mean",
  journal = "ZAMM - Zeitschrift für Angewandte Mathematik und Mechanik",
  volume  = "Vol. 76",
  pages   = "385--390",
  year    = "1996",
}