1. J.H. Anspach, The Case for a National Utility As-Builting Standard, 2011, (accessed 19.11.11).
2. APWA (American Public Works Association), Uniform Color Code, 2005. (accessed 19.11.11).
3. ASCE (American Society of Civil Engineers), Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data, ASCE Codes and Standards Activity Committee (CSAC), New York, NY, 2002.
4. ASCE (American Society of Civil Engineers), Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data, 2011, (accessed 19.11.11).
5. A. Beck, G. Fu, A.G. Cohn, B. Bennett, J.G. Stell, A framework for utility data integration in the UK, in: Proceedings of the 26th Urban Data Management Symposium, Stuttgart, Germany, 2007 (10–12 October).