@article{Jachymski:1995,
  author  = "J. Jachymski and J. Matkowski and T. Świątkowski",
  title   = "Nonlinear contractions on semimetric spaces",
  journal = "Journal of Applied Analysis",
  volume  = "Vol. 1",
  number  = "no 2",
  pages   = "125--134",
  year    = "1995",
}