@article{Matkowski:1990,
  author  = "J. Matkowski",
  title   = "A functional inequality characterizing convex functions, conjugacy and a generalization of Hölder's and Minkowski's inequalities",
  journal = "Aequationes Mathematicae",
  volume  = "Vol. 40",
  number  = "no 2-3",
  pages   = "168--180",
  year    = "1990",
}