1. ASTM (American Society for Testing and Materials) 1985 Annual Book of ASTM Standards. (Section 4: Construction,Vol. 04.08, Soil and Rock; building stones). ASTM, Philadelphia
2. Bishr Y, Molenaar M, Radwan M 1996 Spatial heterogeneity of federated GIS in a client/server architecture. In Proceedings,GIS 96, Vancouver, Canada
3. Buehler K 1996 The Open Geodata Interoperability Specification Part II: Abstract Specification. Draft version. Open GIS Consortium, Wayland, Mass, USA
4. Buehler K, McKee L (eds) 1996 The OpenGIS Guide: Introduction to Interoperable Geoprocessing. Open GIS Consortium, Wayland, Mass, USA
5. Campbell J B 1983 Mapping the Land: Aerial Imagery for Land Use Information. Association of American Geographers, Washington DC