@article{241508,
      note = {Distributed to depository libraries in microfiche.},
      author = {Grim, Muriel S.},
      url = {http://library.usi.edu/record/241508},
      title = {An introduction to MAPGEN [microform] /},
      publisher = {U.S. Dept. of the Interior, U.S. Geological Survey ;},
      recid = {241508},
      pages = {1 v. (various pagings) :},
      address = {[Reston, VA] :},
      year = {1992},
}