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