@article{Kondej:2007,
  author  = "S. Kondej and I. Veseliĉ",
  title   = "Lower bounds on the lowest spectral gap of singular potential Hamiltonians",
  journal = "Annales Henri Poincaré",
  volume  = "Vol. 8",
  number  = "no 1",
  pages   = "109--134",
  year    = "2007",
}