http://reply.papertrans.cn/1/80/7952/7952-21.png
Submitted on: 15 July 2015.
Revised on: 19 October 2015.
Accepted on: 04 December 2015.
___________________Economic Papers---WILEY
http://reply.papertrans.cn/1/80/7952/7952-23.png
http://reply.papertrans.cn/1/80/7952/7952-24.png
http://reply.papertrans.cn/1/80/7952/7952-25.png
http://reply.papertrans.cn/1/80/7952/7952-26.png
http://reply.papertrans.cn/1/80/7952/7952-27.png
Submitted on: 03 June 2001.
Revised on: 25 June 2001.
Accepted on: 13 July 2001.
___________________Economic Papers---WILEY
Submitted on: 16 December 2001.
Revised on: 05 February 2002.
Accepted on: 26 February 2002.
___________________Economic Papers---WILEY
Submitted on: 30 July 2009.
Revised on: 01 October 2009.
Accepted on: 31 October 2009.
___________________Economic Papers---WILEY