@article{Howitt:225861,
      recid = {225861},
      author = {Howitt, Richard},
      title = {POSITIVE MATHEMATICAL PROGRAMMING},
      address = {1991},
      number = {1570-2016-133558},
      series = {91-9},
      pages = {39},
      year = {1991},
      url = {http://ageconsearch.umn.edu/record/225861},
      doi = {https://doi.org/10.22004/ag.econ.225861},
}