Submitted on: 21 December 2002.
Revised on: 22 March 2003.
Accepted on: 22 April 2003.
___________________Communications in Mathematics and Applications
Submitted on: 08 February 2018.
Revised on: 24 March 2018.
Accepted on: 07 April 2018.
___________________Communications in Mathematics and Applications
Submitted on: 13 March 2006.
Revised on: 09 July 2006.
Accepted on: 28 July 2006.
___________________Communications in Mathematics and Applications
Submitted on: 26 August 2023.
Revised on: 09 December 2023.
Accepted on: 24 January 2024.
___________________Communications in Mathematics and Applications
Submitted on: 14 August 2024.
Revised on: 09 November 2024.
Accepted on: 14 December 2024.
___________________Communications in Mathematics and Applications
Submitted on: 23 July 2021.
Revised on: 10 September 2021.
Accepted on: 30 September 2021.
___________________Communications in Mathematics and Applications
Submitted on: 04 August 1998.
Revised on: 14 September 1998.
Accepted on: 18 October 1998.
___________________Communications in Mathematics and Applications
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