Natural versus anthropogenic accumulation of organic matter - a palaeolimnological evidence from a small stratified lake in southern EstoniaAlliksaar, Tiiu; Heinsalu, Atko; Leeben, Aina12th Nordic-Baltic IHSS Symposium on Natural Organic Matter in Environment and Technology : Tallinn, Estonia, June 14-17, 2009 : program and abstracts2009 / p. 52