@article{IR,
      author = {Walinsky, Clifford},
      url = {http://digitalcollections.ohsu.edu/record/3825},
      title = {Constructive negation in Horn-clause programs},
      abstract = {cse-86-003},
      number = {IR},
      doi = {https://doi.org/10.6083/d217qp82v},
      recid = {3825},
      address = {1986},
}