Helman89'

BibTeX

@article{DBLP:journals/acta/Helman89,
  author    = {Paul Helman},
  title     = {A Family of NP-Complete Data Aggregation Problems},
  journal   = {Acta Inf.},
  volume    = {26},
  number    = {5},
  year      = {1989},
  pages     = {485-499},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}