Submitted on: 22 May 2001.
Revised on: 15 June 2001.
Accepted on: 08 August 2001.
___________________JOURNAL OF THE KOREAN MATHEMATICAL SOCIETY
http://reply.papertrans.cn/2/198/19784/19784-22.png
http://reply.papertrans.cn/2/198/19784/19784-23.png
Submitted on: 19 February 2004.
Revised on: 09 May 2004.
Accepted on: 01 July 2004.
___________________JOURNAL OF THE KOREAN MATHEMATICAL SOCIETY
Submitted on: 10 November 2005.
Revised on: 29 December 2005.
Accepted on: 07 February 2006.
___________________JOURNAL OF THE KOREAN MATHEMATICAL SOCIETY
Submitted on: 19 August 2013.
Revised on: 14 September 2013.
Accepted on: 27 September 2013.
___________________JOURNAL OF THE KOREAN MATHEMATICAL SOCIETY
http://reply.papertrans.cn/2/198/19784/19784-27.png
http://reply.papertrans.cn/2/198/19784/19784-28.png
http://reply.papertrans.cn/2/198/19784/19784-29.png
http://reply.papertrans.cn/2/198/19784/19784-30.png