@article{3855,
      author       = "Wray, James R. and Sixth Int´1. Cartographic Assoc.
                      Conference, Technical Session on Urban Cartography, Ottawa,
                      Canada, August 24, 1972",
      title        = "Cartographic Aspects of an Operational System for Detecting
                      Urban Change by Remote Sensing  ",
      year         = "1972",
      note         = "Publication authorized by Director, U.S. Geological Survey.
                      Prepared for presentation., 1 seš.",
}