@article{17779,
      author = {Weller, J. Marvin and Grogan, Robert Mann, and Tippie,  Frank Emerson,},
      url = {http://library.usi.edu/record/17779},
      title = {Geology of the fluorspar deposits of Illinois},
      publisher = {State Geological Survey,},
      recid = {17779},
      pages = {147 p. :},
      address = {Urbana,},
      year = {1952},
}