http://reply.papertrans.cn/3/233/23247/23247-11.png
Submitted on: 09 January 2002.
Revised on: 14 February 2002.
Accepted on: 24 February 2002.
North American Journal of Economics and Finance
http://reply.papertrans.cn/3/233/23247/23247-13.png
Submitted on: 21 August 2006.
Revised on: 02 September 2006.
Accepted on: 15 September 2006.
North American Journal of Economics and Finance
Submitted on: 10 March 2004.
Revised on: 16 April 2004.
Accepted on: 13 May 2004.
North American Journal of Economics and Finance
Submitted on: 29 March 2012.
Revised on: 08 April 2012.
Accepted on: 21 April 2012.
North American Journal of Economics and Finance
http://reply.papertrans.cn/3/233/23247/23247-17.png
Submitted on: 17 July 2001.
Revised on: 27 July 2001.
Accepted on: 16 August 2001.
North American Journal of Economics and Finance
http://reply.papertrans.cn/3/233/23247/23247-19.png
http://reply.papertrans.cn/3/233/23247/23247-20.png