1. EN 50341–1: Overhead electrical lines exceeding AC 45 kV. Part 1: General requirements – Common specifications. Brussels, CENELEC, 2001
2. DIN 4022: Subsoil and groundwater. Classification and description of soil and rock. Part 1: Borehole logging of soil and rock not involving continuous core sample recovery. Berlin, DIN, 1987 Part 2: Borehole logging of rock. Berlin, DIN, 1987 Part 3: Borehole logging for boringin soil (loose rock) by continuous extraction of cores. Berlin, DIN, 1987
3. IEC 61 773: Overhead lines. Testing of foundations of supports. Geneva, IEC, 1997
4. DIN 1054: Subsoil; Permissible loading of subsoil. Berlin, DIN, 1976
5. DIN 4021: Subsoil; Ground exploration by excavation, boring and sampling. Berlin, DIN, 1990