1. Standard Methods for the Examination of Water and Wastewater;APHA,1971
2. Standard Methods for the Examination of Water and Wastewater;APHA,1976
3. Determination of tannin substances in boiler waters;Berk;Ind. Engng Chem.,1942
4. Chemical characteristics of fulvic acids;Black;J. Am. Wat. Wks Ass.,1963
5. Chemische Probleme der gefärbten organischen Stoffe in Oberfläehengewässern;Chalupa;Mitt. int. Verein. theor. angew. Limnol.,1968