http://reply.papertrans.cn/3/270/26907/26907-31.png
Submitted on: 06 May 2002.
Revised on: 28 May 2002.
Accepted on: 13 June 2002.
NULL
Submitted on: 11 May 1998.
Revised on: 29 May 1998.
Accepted on: 03 June 1998.
NULL
http://reply.papertrans.cn/3/270/26907/26907-34.png
Submitted on: 19 October 2006.
Revised on: 28 October 2006.
Accepted on: 15 November 2006.
NULL
http://reply.papertrans.cn/3/270/26907/26907-36.png