@article{Exner:2004,
  author  = "P. Exner and S. Kondej",
  title   = "Schrödinger operators with singular interactions: a model of tunneling resonances",
  journal = "Journal of Physics A : Mathematical and General",
  volume  = "Vol. 37",
  pages   = "8255--8277",
  year    = "2004",
}