Submitted on: 15 September 2006.
Revised on: 15 October 2006.
Accepted on: 05 November 2006.
NULL
Submitted on: 03 April 2019.
Revised on: 25 April 2019.
Accepted on: 03 May 2019.
NULL
http://reply.papertrans.cn/3/252/25149/25149-23.png
Submitted on: 18 August 2008.
Revised on: 09 September 2008.
Accepted on: 19 September 2008.
NULL
http://reply.papertrans.cn/3/252/25149/25149-25.png
http://reply.papertrans.cn/3/252/25149/25149-26.png
Submitted on: 31 January 2005.
Revised on: 08 March 2005.
Accepted on: 24 March 2005.
NULL
http://reply.papertrans.cn/3/252/25149/25149-28.png
http://reply.papertrans.cn/3/252/25149/25149-29.png
Submitted on: 05 September 1999.
Revised on: 22 September 1999.
Accepted on: 12 October 1999.
NULL