Chemical analysis of temporal changes in the structure and quantity of organic biomolecules of lake sedimentsLepane, Viia; Makarõtševa, Natalja; Viitak, Anu; Alliksaar, TiiuInternational Humic Substances Society 11th Nordic-Baltic Symposium. Functioning of NOM in the Environment : Joensuu, Finland, June 10-13 : abstracts2007 / p. 42