@article{20423,
      recid = {20423},
      author = {Popp, John T.},
      title = {Investigation of the gas content of coal seams in the  vicinity of Charleston, Illinois /},
      publisher = {State of Illinois, Institute of Natural Resources,},
      address = {Chicago :},
      pages = {v, 36 p. :},
      year = {1979},
      url = {http://library.usi.edu/record/20423},
}