@article{200506,
      note = {Cover title.},
      author = {Yager, Douglas B. and Lipman, Peter W. and Sawyer, David  A.},
      url = {http://library.usi.edu/record/200506},
      title = {Caldera-related lava flows and intrusions of the  south-central San Juan Mountains, Colorado analytical data  / [microform] :},
      publisher = {U.S. Geological Survey ;},
      recid = {200506},
      pages = {19 leaves :},
      address = {Denver, Colo. :},
      year = {1991},
}