Authors
Hristo Chervenkov
National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, 1784, Sofia, Bulgaria
Vladimir Ivanov
National Institute in Geophysics, Geodesy and Geography, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
Georgi Gadzhev
National Institute in Geophysics, Geodesy and Geography, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
Kostadin Ganev
National Institute in Geophysics, Geodesy and Geography, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
