• Field investigations of apparent optical properties of ice cover in Finnish and Estonian lakes in winter 2009Lei, Ruibo; Leppäranta, Matti; Erm, Ants; Jaatinen, Elina; Pärn, OveEstonian journal of earth sciences2011 / 1, lk. 50-64 : ill https://artiklid.elnet.ee/record=b2284374*est