1. Humic Acids;Oden;Kolloidchem. Beihefte,1919
2. Humic Acids in Water. I. Methods of Preparation and Determination;Chalupa;Sborník VŠCHT-Praha, FTPV,1963
3. Hedlund , I. Wilson , K. Determination of Sulphite Pulp Liquor in Water Streams Paperstidning Svensk 582 1957
4. Light Absorption Measurement in UV-range as a Tool for Estimation of Water Quality in Power Industry;Fähnrich;Energetika,1961
5. Light Absorption Measurement in UV-range as a Tool for Estimation of Water Quality in Power Industry;Fähnrich;Energetika,1962