@article{216111,
      author = {Battaglin, William A.},
      url = {http://library.usi.edu/record/216111},
      title = {Plan of study to determine if the isotopic ratios [delta]  ¹⁵N and [delta] ¹⁸O can reveal the sources of nitrate  discharged by the Mississippi River into the Gulf of Mexico  /},
      publisher = {U.S. Geological Survey :},
      recid = {216111},
      pages = {iv, 18 p. :},
      address = {Denver, Colo. :},
      year = {1997},
}