@article{216816,
      note = {Cover title.},
      author = {Singer, D. A. and Menzie W. David. and Long, Keith R.},
      url = {http://library.usi.edu/record/216816},
      title = {A simplified economic filter for open-pit gold-silver  mining in the United States /},
      publisher = {U.S. Geological Survey,},
      recid = {216816},
      pages = {10 p. :},
      address = {[Menlo Park, CA] :},
      year = {1998},
}