@inproceedings{ijcai1975p47,
  title     = {An Improved Di-Directional Heuristic Search Algorithm},
  author    = {de Champeaux, Dennis and Sint, Lenie},
  booktitle = {Proceedings of the Fourth International Joint Conference on
               Artificial Intelligence, {IJCAI-75}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Patrick Winston and Carl Hewitt},
  pages     = {309--313},
  year      = {1975},
  note      = {Search Techniques},
  url       = {https://ijcai.org/proceedings/1975/47},
}