Johnson, A. I., Pettersson, C. B., & Fulton, J. L. (1992). Geographic information systems (GIS) and mapping-practices and standards. Philadelphia, PA.: ASTM.
Παραπομπή Chicago StyleJohnson, A. I., C. B. Pettersson, and J. L. Fulton. Geographic Information Systems (GIS) and Mapping-practices and Standards. Philadelphia, PA.: ASTM, 1992.
Παραπομπή MLAJohnson, A. I., C. B. Pettersson, and J. L. Fulton. Geographic Information Systems (GIS) and Mapping-practices and Standards. Philadelphia, PA.: ASTM, 1992.
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