@inproceedings{ijcai1993p65,
  title     = {PHI - A Logic-Based Tool for Intelligent Help Systems},
  author    = {Bauer, Mathias and Biundo, Susanne and Dengler, Dietmar and Koehler, Jana and Paul, Gabriele},
  booktitle = {Proceedings of the Thirteenth International Joint Conference on
               Artificial Intelligence, {IJCAI-93}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Ruzena Bajcsy},
  pages     = {460--465},
  year      = {1993},
  note      = {Intelligent Tutoring Systems},
  url       = {https://ijcai.org/proceedings/1993/65},
}