1. Anonymous (1994) ZTG, BGBI. I Nr. 156/1994 (Official Austrian Government Gazette, Vienna) Bundesgesetz über Ziviltechniker 1994.
2. Anonymous (2003) DIN 4020. Geotechnical investigations for civil engineering purposes (Beuth, Berlin).
3. Anonymous (2004) Eurocode 7. Geotechnical design—EN 1997-1. Part 1: General rules, European Committee for Standardization, Brussels.
4. Anonymous (2007) Eurocode 7. Geotechnical design—EN 1997-2. Part 2: Ground investigation and testing (European Committee for Standardization, Brussels).
5. The Joint European Working Group of the ISSMGE, ISRM and IAEG for the definition of professional tasks, responsibilities and co-operation in ground engineering;Bock,2004