German standard methods for the analysis of water, waste water and sludge; Sludge and sediments (group S); Determination of pH value in sludge and sediments (S 5)— 4 стр.
German standard methods for the examination of water, waste water and sludge; sludge and sediments (group S); determination of the amenability to anaerobic digestion (S 8)— 12 стр.
