@article{Heffernan:137533,
      recid = {137533},
      author = {Heffernan, Peter J.},
      title = {Agricultural Letter},
      journal = {Agricultural Letter},
      address = {1987-10-09},
      number = {820-2016-52921},
      series = {1718},
      pages = {4},
      month = {Oct},
      year = {1987},
      url = {http://ageconsearch.umn.edu/record/137533},
      doi = {https://doi.org/10.22004/ag.econ.137533},
}