Submitted on: 02 August 2014.
Revised on: 13 September 2014.
Accepted on: 29 September 2014.
University Politehnica of Bucharest Scientific Bulletin-Series A-Applied Mathematics and Physics
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Submitted on: 16 May 2009.
Revised on: 15 June 2009.
Accepted on: 02 July 2009.
University Politehnica of Bucharest Scientific Bulletin-Series A-Applied Mathematics and Physics
Submitted on: 06 December 2019.
Revised on: 18 December 2019.
Accepted on: 13 January 2020.
University Politehnica of Bucharest Scientific Bulletin-Series A-Applied Mathematics and Physics
Submitted on: 08 August 2008.
Revised on: 12 September 2008.
Accepted on: 04 October 2008.
University Politehnica of Bucharest Scientific Bulletin-Series A-Applied Mathematics and Physics
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Submitted on: 20 April 2017.
Revised on: 29 May 2017.
Accepted on: 24 June 2017.
University Politehnica of Bucharest Scientific Bulletin-Series A-Applied Mathematics and Physics
http://reply.papertrans.cn/4/302/30178/30178-18.png
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Submitted on: 16 August 2021.
Revised on: 19 September 2021.
Accepted on: 28 September 2021.
University Politehnica of Bucharest Scientific Bulletin-Series A-Applied Mathematics and Physics