@article{Heffernan:137532,
      recid = {137532},
      author = {Heffernan, Peter J. and Benjamin, Gary L.},
      title = {Agricultural Letter},
      journal = {Agricultural Letter},
      address = {1984-10},
      number = {820-2016-53363},
      series = {1640},
      pages = {4},
      year = {1984},
      url = {http://ageconsearch.umn.edu/record/137532},
      doi = {https://doi.org/10.22004/ag.econ.137532},
}