@Article{ 
  Kov13,
  author = { Kovarik, Hynek },
  title = { On the lowest eigenvalue of Laplace operators with mixed boundary conditions },
  journal = { J. Geom. Anal. },
  year = { 2014 },
  doi = { 10.1007/s12220-012-9383-4 },
  volume = { 24 },
  pages = { 16 },
  URL = { http://cvgmt.sns.it/paper/2320/ },
  note = { cvgmt preprint}
}