@inproceedings{ijcai1989p109,
  title     = {Abstraction in Problem Solving and Learning},
  author    = {Unruh, Amy and Rosenbloom, Paul S.},
  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     = {681--686},
  year      = {1989},
  month     = {8},
  note      = {Machine Learning},
  url       = {https://ijcai.org/proceedings/1989/109},
}