Submitted on: 10 April 2000.
Revised on: 30 April 2000.
Accepted on: 07 May 2000.
Proceedings of the Institute of Mathematics and Mechanics
Submitted on: 29 October 2011.
Revised on: 09 November 2011.
Accepted on: 30 November 2011.
Proceedings of the Institute of Mathematics and Mechanics
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Submitted on: 23 November 2002.
Revised on: 22 December 2002.
Accepted on: 02 January 2003.
Proceedings of the Institute of Mathematics and Mechanics
http://reply.papertrans.cn/3/253/25285/25285-15.png
Submitted on: 26 July 2017.
Revised on: 09 August 2017.
Accepted on: 03 September 2017.
Proceedings of the Institute of Mathematics and Mechanics
http://reply.papertrans.cn/3/253/25285/25285-17.png
http://reply.papertrans.cn/3/253/25285/25285-18.png
http://reply.papertrans.cn/3/253/25285/25285-19.png
Submitted on: 21 February 2016.
Revised on: 18 March 2016.
Accepted on: 30 March 2016.
Proceedings of the Institute of Mathematics and Mechanics