Skaisgiriene, A., P. Vaitiekūnas, and V. Zabukas. “Influence of Chlorides and Sulphates on Quality of Biological Wastewater Treatment Using Enzyme Preparations”. Journal of Environmental Engineering and Landscape Management, vol. 12, no. 3, Sept. 2004, pp. 91-95, doi:10.3846/16486897.2004.9636825.