@article{DBLP:journals/ai/HanssonMV92,
  author    = {Othar Hansson and
               Andrew Mayer and
               Marco Valtorta},
  title     = {A New Result on the Complexity of Heuristic Estimates for
               the A* Algorithm},
  journal   = {Artif. Intell.},
  volume    = {55},
  number    = {1},
  year      = {1992},
  pages     = {129-143},
  ee        = {http://dx.doi.org/10.1016/0004-3702(92)90045-Y},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}