1. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 9, 1113 Sofia, Bulgaria
2. Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 103A, 1113 Sofia, Bulgaria
3. Bulgarian Academy of Sciences, №1, 15 Noemvri St., 1040 Sofia, Bulgaria