DIN 18312:2019-09 German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Underground construction work
2019DIN 18312:2019-09 German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Underground construction work
2012DIN 18312:2012 German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Underground construction work