Institution: | 1. New Bulgarian University, 21 Montevideo str., 1618 Sofia, Bulgaria;2. Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, 8 Acad. G. Bonchev str., 1113 Sofia, Bulgaria;3. Faculty of Mathematics and Informatics, 5 J. Bourchier Blvd., 1164 Sofia, Bulgaria;4. Sobolev Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences, 4 Acad. Koptyug avenue, 630090 Novosibirsk, Russia |