Central drinking water supply - Guide lines regarding requirements for drinking water, planning, construction, operation and maintenance of plants - Technical rule of the DVGW— 10 стр.
German Standard Methods for Examination of Water, Waste Water and Sludge; Summary Action and Material Characteristic Parameters (Group H); Determination of the Chemical Oxygen Demand (COD) in the Range over 15 mg/l (H41)— 14 стр.
Environmental management systems - Requirements with guidance for use (ISO 14001:2004 + Cor. 1:2009); German and English version EN ISO 14001:2004 + AC:2009— 52 стр.
