@inproceedings{Nielsen88,
  title = {A Qualitative Approach to Mechanical Constraint},
  author = {Paul Nielsen},
  year = {1988},
  tags = {constraints, systematic-approach},
  researchr = {https://researchr.org/publication/Nielsen88},
  cites = {0},
  citedby = {0},
  pages = {270-274},
  booktitle = {AAAI},
}