1. Department of Physico-Chemical Mechanics, Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria
2. Instituto de Ciencia y Tecnología de Polímeros, ICTP-CSIC, Juan de la Cierva 3, Madrid, Spain
3. Centro de Biomateriales, Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, Spain
4. University of Chemical Technology and Metallurgy (UCTM), Sofia, Bulgaria
5. Faculty of Physics, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria