@misc{W2080142817,
  author = {Sarit Kraus and Daniel Lehmann and Menachem Magidor},
  title = {Nonmonotonic reasoning, preferential models and cumulative logics},
  year = {1990},
  howpublished = {Artificial Intelligence},
  doi = {https://doi.org/10.1016/0004-3702(90)90101-5}
}