@article{184676,
      note = {Distributed to depository libraries in microfiche.},
      author = {Listak, Jeffrey M. and Bauer, Eric R.},
      url = {http://library.usi.edu/record/184676},
      title = {Longwall retreat of gate road pillars [microform] /},
      publisher = {U.S. Dept. of the Interior, Bureau of Mines,},
      recid = {184676},
      pages = {11 p. :},
      address = {Washington, D.C. (810 7th St., N.W., Washington  20241-0001) :},
      year = {1993},
}