@article{222920,
      note = {Relief shown by contours and spot heights.},
      author = {Drake, Avery Ala,},
      url = {http://library.usi.edu/record/222920},
      title = {Geologic map of the Kensington quadrangle, Montgomery  County, Maryland [microform] /},
      publisher = {The Survey ;},
      recid = {222920},
      pages = {1 map.},
      address = {Reston, VA :},
      year = {1998},
}