Dimitar Nikolov. "SNOW BLIZZARDS AND SNOW DRIFTS IN NORTEAST BULGARIA - ASSESSMENT AND RECENT TENDENCIES." SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 18th International Multidisciplinary Scientific GeoConference SGEM2018, Energy and Clean Technologies (2018): 591-598. https://doi.org/10.5593/sgem2018/4.2/s19.076