Submitted on: 30 August 2018.
Revised on: 29 September 2018.
Accepted on: 11 October 2018.
Research in Economics---ELSEVIER SCI LTD
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http://reply.papertrans.cn/3/265/26403/26403-33.png
Submitted on: 08 December 2017.
Revised on: 31 December 2017.
Accepted on: 12 January 2018.
Research in Economics---ELSEVIER SCI LTD
Submitted on: 17 September 2004.
Revised on: 14 October 2004.
Accepted on: 30 October 2004.
NULL
Submitted on: 13 April 2014.
Revised on: 30 April 2014.
Accepted on: 23 May 2014.
Research in Economics---ELSEVIER SCI LTD