Submitted on: 21 November 2002.
Revised on: 11 February 2003.
Accepted on: 22 February 2003.
___________________Journal of Demographic Economics
Submitted on: 13 June 2011.
Revised on: 06 July 2011.
Accepted on: 24 August 2011.
___________________Journal of Demographic Economics
Submitted on: 21 October 2012.
Revised on: 17 December 2012.
Accepted on: 05 January 2013.
___________________Journal of Demographic Economics
Submitted on: 14 March 2010.
Revised on: 26 April 2010.
Accepted on: 17 May 2010.
___________________Journal of Demographic Economics
http://reply.papertrans.cn/2/163/16287/16287-15.png
Submitted on: 25 September 2013.
Revised on: 29 October 2013.
Accepted on: 15 November 2013.
___________________Journal of Demographic Economics
http://reply.papertrans.cn/2/163/16287/16287-17.png
Submitted on: 11 November 2017.
Revised on: 14 December 2017.
Accepted on: 01 February 2018.
___________________Journal of Demographic Economics
http://reply.papertrans.cn/2/163/16287/16287-19.png
http://reply.papertrans.cn/2/163/16287/16287-20.png