1. State Drug Agency, 26, Janko Sakazov Blvd., 1505 Sofia, Bulgaria
2. Institute of Botany, Bulgarian Academy of Sciences, 1, Acad. Georgy Bonchev St., 1113 Sofia, Bulgaria
3. Institute of Microbiology, Bulgarian Academy of Sciences, 26, Acad. Georgy Bonchev St., 1113 Sofia, Bulgaria