Fluorescence spectroscopy of sedimentary pore-water humic substances : a simple tool for retrospective analysis of lake ecosystemsLeeben, Aina; Mikomägi, Annika; Lepane, Viia; Alliksaar, TiiuJournal of soils and sediments2014 / p. 269-279 : illhttps://doi.org/10.1007/s11368-013-0768-1