Valery Covachev
Associate Professor, PhD,
Mathematical Physics Department,
Institute of Mathematics and Informatics,
Bulgarian Academy of Sciences,
Acad.G.Bonchev str. 8, 1113 Sofia, Bulgaria
Current address: Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, Muscat 123, Sultanate of Oman.
E-mail: valery@squ.edu.om