@article{Borowiecki:2000,
  author  = "M. Borowiecki and I. Broere and P. Mihok",
  title   = "Minimal reducible bounds for planar graphs",
  journal = "Discrete Mathematics",
  volume  = "Vol. 212",
  number  = "no 1-2",
  pages   = "19--27",
  year    = "2000",
}