@inproceedings{ijcai1989p8,
  title     = {Platypus: A Constraint-Based Reasoning System},
  author    = {Havens, William S. and Rehfuss, Paul Stephen},
  booktitle = {Proceedings of the Eleventh International Joint Conference on
               Artificial Intelligence, {IJCAI-89}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {N. S. Sridharan},
  pages     = {48--52},
  year      = {1989},
  month     = {8},
  note      = {Tools},
  url       = {https://ijcai.org/proceedings/1989/8},
}