@article{8200,
      recid = {8200},
      title = {Coal resource classification system of the U.S. Bureau of  Mines and U.S. Geological Survey : a report /},
      publisher = {U.S. Govt. Print. Off.,},
      address = {Washington :},
      pages = {v, 7 p. ;},
      year = {1976},
      note = {"Definitions of coal resource classification terms used by  the U.S. Bureau of Mines and U.S. Geological Survey."},
      url = {http://library.usi.edu/record/8200},
}