@article{Cox:163401,
      recid = {163401},
      author = {Cox, Nicholas J.},
      title = {Stata tip 68: Week assumptions},
      journal = {Stata Journal},
      address = {2010},
      number = {199-2016-2716},
      pages = {4},
      year = {2010},
      url = {http://ageconsearch.umn.edu/record/163401},
      doi = {https://doi.org/10.22004/ag.econ.163401},
}