Submitted on: 27 April 2014.
Revised on: 02 June 2014.
Accepted on: 25 June 2014.
NULL
http://reply.papertrans.cn/3/265/26419/26419-22.png
http://reply.papertrans.cn/3/265/26419/26419-23.png
Submitted on: 22 July 1999.
Revised on: 03 September 1999.
Accepted on: 25 September 1999.
NULL
Submitted on: 02 December 2012.
Revised on: 09 December 2012.
Accepted on: 17 December 2012.
Research in Mathematics Education
http://reply.papertrans.cn/3/265/26419/26419-26.png
Submitted on: 20 August 2009.
Revised on: 21 September 2009.
Accepted on: 05 October 2009.
NULL
http://reply.papertrans.cn/3/265/26419/26419-28.png
http://reply.papertrans.cn/3/265/26419/26419-29.png
Submitted on: 17 April 2014.
Revised on: 09 May 2014.
Accepted on: 26 May 2014.
NULL