http://reply.papertrans.cn/3/289/28810/28810-31.png
Submitted on: 24 May 2008.
Revised on: 06 June 2008.
Accepted on: 20 June 2008.
NULL
Submitted on: 14 January 2007.
Revised on: 20 February 2007.
Accepted on: 12 March 2007.
NULL
http://reply.papertrans.cn/3/289/28810/28810-34.png
Submitted on: 10 October 1998.
Revised on: 04 November 1998.
Accepted on: 30 November 1998.
NULL
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