Submitted on: 18 January 2005.
Revised on: 24 March 2005.
Accepted on: 19 May 2005.
___________________Bulletin of the Iranian Mathematical Society
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Submitted on: 08 September 2018.
Revised on: 18 December 2018.
Accepted on: 05 January 2019.
___________________Bulletin of the Iranian Mathematical Society
http://reply.papertrans.cn/1/44/4374/4374-14.png
http://reply.papertrans.cn/1/44/4374/4374-15.png
Submitted on: 11 December 2005.
Revised on: 06 February 2006.
Accepted on: 25 March 2006.
___________________Bulletin of the Iranian Mathematical Society
Submitted on: 10 September 2007.
Revised on: 09 December 2007.
Accepted on: 24 January 2008.
___________________Bulletin of the Iranian Mathematical Society
Submitted on: 25 April 2009.
Revised on: 14 June 2009.
Accepted on: 30 July 2009.
___________________Bulletin of the Iranian Mathematical Society
Submitted on: 04 January 2016.
Revised on: 09 February 2016.
Accepted on: 19 February 2016.
___________________Bulletin of the Iranian Mathematical Society
Submitted on: 25 July 2013.
Revised on: 03 October 2013.
Accepted on: 26 November 2013.
___________________Bulletin of the Iranian Mathematical Society