@inproceedings{ijcai1973p53,
  title     = {Planning in a Hierarchy of Abstraction Spaces},
  author    = {Sacerdoti, Earl D.},
  booktitle = {Proceedings of the Third International Joint Conference on
               Artificial Intelligence, {IJCAI-73}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Nils J. Nilsson},
  pages     = {412--421},
  year      = {1973},
  month     = {8},
  note      = {Robot Problem Solving},
  url       = {https://ijcai.org/proceedings/1973/53},
}