1. Institute of Mineralogy and Crystallography “Аkad. I. Kostov”, Bulgarian Academy of Sciences, “Akad. G. Bonchev” St., Bl. 107, 1113 Sofia, Bulgaria
2. Institute of Catalysis, Bulgarian Academy of Sciences, “Acad. G. Bonchev” St., Block 11, 1113 Sofia, Bulgaria
3. Institute of Polymers, Bulgarian Academy of Sciences, “Akad. G. Bonchev” St., Bl.103A, 1113 Sofia, Bulgaria