@article{198948,
      note = {Relief shown by contours and spot heights.},
      author = {Jachens, Robert C.},
      url = {http://library.usi.edu/record/198948},
      title = {Aeromagnetic map of the El Cajón 1:100,000 scale  quadrangle, California [microform] /},
      publisher = {The Survey ;},
      recid = {198948},
      pages = {1 map ;},
      address = {[Reston, Va.?] :},
      year = {1992},
}