Department of Geophysics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, Prague, 18000 Czech Republic ; Section 1.3, GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, D-14473 Germany
Department of Geophysics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, Prague, 18000 Czech Republic ; Center of Earth's Dynamics Research, Research Institute of Geodesy, Topography and Cartography, Geodetical observatory Pecný, Ondřejov 244, 25165 Czech Republic
Department of Geoelectricity, Geophysical Institute of the Academy of Sciences, Boční II/1401, Prague, 14131 Czech Republic