1. University of Illinois, Illinois State Water Survey, 1506 Coral Cove Drive, Champaign, Illinois 61821, United States
2. Department of Geosciences, Texas Tech University, Lubbock, Texas 79409-1053, United States
3. Institute of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic
4. Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic