Submitted on: 23 January 2005.
Revised on: 19 February 2005.
Accepted on: 09 March 2005.
NULL
Submitted on: 17 November 2008.
Revised on: 11 December 2008.
Accepted on: 24 December 2008.
Journal on Efficiency and Responsibility in Education and Science
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Submitted on: 19 September 2008.
Revised on: 19 October 2008.
Accepted on: 13 November 2008.
NULL
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