Submitted on: 27 March 2019.
Revised on: 23 April 2019.
Accepted on: 12 May 2019.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
Submitted on: 03 October 2011.
Revised on: 30 October 2011.
Accepted on: 14 November 2011.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
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http://reply.papertrans.cn/3/215/21457/21457-34.png
Submitted on: 22 May 2014.
Revised on: 28 June 2014.
Accepted on: 17 July 2014.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
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