Sofia University "St. Kliment Ohridski" Technical University - Sofia Bulgarian Academy of Science University "Prof. Dr. Assen Zlatarov" - Burgas Plovdiv University Paisii Hilendarski University of Chemical Technology and Metallurgy "Angel Kanchev" University of Ruse Konstantin Preslavsky University of Shumen Medical University Sofia Technical University Varna State University of Library Studies and Information Technologies South-West University "Neofit Rilski"
