Submitted on: 03 September 2019.
Revised on: 17 December 2019.
Accepted on: 31 December 2019.
___________________Differential Equations & Applications
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Submitted on: 04 August 2023.
Revised on: 20 September 2023.
Accepted on: 08 November 2023.
___________________Differential Equations & Applications
Submitted on: 05 November 2017.
Revised on: 28 February 2018.
Accepted on: 18 April 2018.
___________________Differential Equations & Applications
Submitted on: 18 February 2006.
Revised on: 07 May 2006.
Accepted on: 29 May 2006.
___________________Differential Equations & Applications
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