Authors
Hristo Chervenkov
National Institute of Meteorology and Hydrology (NIMH), Sofia, Bulgaria
Vladimir Ivanov
National Institute of Geophysics, Geodesy and Geography - Bulgarian Academy of Sciences (NIGGG-BAS), Sofia, Bulgaria
Georgi Gadzhev
National Institute of Geophysics, Geodesy and Geography - Bulgarian Academy of Sciences (NIGGG-BAS), Sofia, Bulgaria
Kostadin Ganev
National Institute of Geophysics, Geodesy and Geography - Bulgarian Academy of Sciences (NIGGG-BAS), Sofia, Bulgaria
Dimitrios Melas
Aristotle University of Thessaloniki, Faculty of Sciences School of Physics, Thessaloniki, Greece
