@article{Matkowski:1993,
  author  = "J. Matkowski and J. Rätz",
  title   = "On the equality condition in Hölder's and Minkowski's inequalities",
  journal = "Aequationes Mathematicae",
  volume  = "Vol. 46",
  number  = "no 3",
  pages   = "220--228",
  year    = "1993",
}