Submitted on: 21 August 2008.
Revised on: 05 October 2008.
Accepted on: 01 November 2008.
___________________Eurasian Economic Review---SPRINGER HEIDELBERG
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Submitted on: 29 April 2016.
Revised on: 10 June 2016.
Accepted on: 15 July 2016.
___________________Eurasian Economic Review---SPRINGER HEIDELBERG
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