@article{Drgas-Burchardt:2007,
  author  = "E. Drgas-Burchardt and E. Łazuka",
  title   = "Chromatic polynomials of hypergraphs",
  journal = "Applied Mathematics Letters",
  volume  = "Vol. 20",
  number  = "no 12",
  pages   = "1250--1254",
  year    = "2007",
}