DVGW 301 Group W1 (German Technical and Scientific Association for Gas and Water)
DVGW 302 Group GN 1 (German Technical and Scientific Association for Gas and Water)
Quality assurance channel build RAL-GZ 961
QGS - S 1, S 2, S 3
Pre-Qualification VOB (German Contract Procedures for Construction Work)
Chamber of Commerce in Berlin
Chamber of Industry and Commerce in Berlin
