@article{Drgas-Burchardt:2009,
  author  = "E. Drgas-Burchardt",
  title   = "On 3-chromatically unique and 3-chromatically equivalent hypergraphs",
  journal = "Ars Combinatoria",
  volume  = "Vol. 93",
  pages   = "409--415",
  year    = "2009",
}