Submitted on: 18 December 2010.
Revised on: 09 February 2011.
Accepted on: 10 March 2011.
___________________Italian Journal of Pure and Applied Mathematics
Submitted on: 28 November 2003.
Revised on: 21 February 2004.
Accepted on: 17 March 2004.
___________________Italian Journal of Pure and Applied Mathematics
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Submitted on: 02 September 1998.
Revised on: 21 November 1998.
Accepted on: 16 January 1999.
___________________Italian Journal of Pure and Applied Mathematics
Submitted on: 06 April 2013.
Revised on: 22 May 2013.
Accepted on: 07 July 2013.
___________________Italian Journal of Pure and Applied Mathematics
Submitted on: 06 August 2007.
Revised on: 03 October 2007.
Accepted on: 18 November 2007.
___________________Italian Journal of Pure and Applied Mathematics
Submitted on: 23 September 2023.
Revised on: 15 January 2024.
Accepted on: 11 March 2024.
___________________Italian Journal of Pure and Applied Mathematics
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