@article{Okrasiński:1998,
  author  = "W. Okrasiński and S. Vila",
  title   = "Determination of the Interface Position for Some Nonlinear Diffusion Problems",
  journal = "Applied Mathematics Letters",
  volume  = "Vol. 11",
  number  = "no 4",
  pages   = "85--89",
  year    = "1998",
}