DIN 18326:2019-09 German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Renovation works on drainage channels
2019DIN 18326:2019-09 German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Renovation works on drainage channels
2012DIN 18326:2012 German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Renovation works on drainage channels