Volume 21, No 6, 2014, P.
UDC
K
Abstract:
We
Keywords:
DOI: 10.17377/daio.2014.21.
Yu 1,2
Al 2
1. S. L. Sobolev Institute of Mathematics, SB RAS,
4 Acad. Koptyug Ave., 630090 Novosibirsk, Russia
2.
Novosibirsk State University,
2 Pirogov St., 630090 Novosibirsk, Russia
e-mail:
