@InCollection{Karwowski:2002,
  author    = "W. Karwowski and S. Kondej",
  title     = "The Laplace operator, null set perturbations and boundary conditions",
  pages     = "233--244",
  year      = "2002",
  booktitle = "Operator methods in ordinary and partial differential equations : Kovalevsky Symposium, University of Stockholm, june 2000, ISBN: 3764367903",
  publisher = "Birkhäuser Verlag AG",
  address   = "[B.m.]",
  series    = "Operator Theory : Advances and Applications : Vol. 132",
}