The PDF (in Russian): http://www.math.kz/images/journal/2013-4/Otelbaev_N-S_21_12_2013.pdf http://www.math.kz/images/journal/2013-4/Otelbaev_N-S_21_12_... The

The PDF (in Russian): http://www.math.kz/images/journal/2013-4/Otelbaev_N-S_21_12_2013.pdf http://www.math.kz/images/journal/2013-4/Otelbaev_N-S_21_12_... There is a small summary at the end in English, although it only seems to cover the problem: http://i.imgur.com/fVqVBiE.png http://i.imgur.com/fVqVBiE.png