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Submitted on: 15 January 2012.
Revised on: 23 March 2012.
Accepted on: 13 April 2012.
___________________EUROPEAN JOURNAL OF APPLIED MATHEMATICS
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Submitted on: 23 October 1998.
Revised on: 25 January 1999.
Accepted on: 25 March 1999.
___________________EUROPEAN JOURNAL OF APPLIED MATHEMATICS
Submitted on: 08 August 2002.
Revised on: 16 October 2002.
Accepted on: 27 November 2002.
___________________EUROPEAN JOURNAL OF APPLIED MATHEMATICS
Submitted on: 02 June 1999.
Revised on: 30 July 1999.
Accepted on: 24 August 1999.
___________________EUROPEAN JOURNAL OF APPLIED MATHEMATICS
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Submitted on: 04 December 2004.
Revised on: 17 January 2005.
Accepted on: 26 February 2005.
___________________EUROPEAN JOURNAL OF APPLIED MATHEMATICS
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