1. Earth Science Institute, Slovak Academy of Sciences , Dúbravská cesta 9, 840 05 Bratislava , Slovakia
2. Faculty of Mathematics, Physics and Informatics , Comenius University , Mlynská dolina, 842 48 Bratislava , Slovakia
3. State Nature Conservancy of the Slovak Republic, Slovak Caves Administration , Hodžova 11, 031 01 Liptovský Mikuláš, Slovakia