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Submitted on: 09 July 2005.
Revised on: 24 October 2005.
Accepted on: 28 November 2005.
___________________Journal of Siberian Federal University-Mathematics & Physics
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Submitted on: 18 May 2000.
Revised on: 01 September 2000.
Accepted on: 07 October 2000.
___________________Journal of Siberian Federal University-Mathematics & Physics
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Submitted on: 09 October 2014.
Revised on: 23 November 2014.
Accepted on: 08 December 2014.
___________________Journal of Siberian Federal University-Mathematics & Physics
Submitted on: 27 June 2012.
Revised on: 11 August 2012.
Accepted on: 21 August 2012.
___________________Journal of Siberian Federal University-Mathematics & Physics
Submitted on: 16 May 2018.
Revised on: 02 September 2018.
Accepted on: 16 October 2018.
___________________Journal of Siberian Federal University-Mathematics & Physics