The authors wish to thank the anonymous reviewers for their helpful comments and suggestions. They are also grateful to EPJP for their corrections pertaining to the English language.

E. Tala-Tebue, University of Dschang, Bandjoun, Cameroon

I would like to express my gratitude to you for your efforts concerning my manuscript. Your expertise in choosing referee and the referee's valuable comments were excellent guide throughout the process of review.

E.K. Elmaghraby, Nuclear Research Center, Cairo, Egypt

We really appreciate your fast and very professional editing process.

Valérie Vidal, Université de Lyon, Ecole Normale Supérieure de Lyon - CNRS, France

Thank you very much once again for your excellent work.

Ignazio Ciufolini, Università del Salento, Lecce, Italy

Thank you very much for your assistance and quick and excellent handling of the manuscript.

Jakub Bielecki, Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland

On behalf of the authors, I gratefully acknowledge the Editors and the Editorial and Production Office for their attention in the revision and editing of the manuscript.

Davide Rotta, Università di Milano Bicocca, Italy

On behalf of all my colleagues and me, I really appreciate the quick and precise editorial process on this paper. That made our work much better, which assisted us in achieving our goal.

Farnaz Foadi, Plasma Physics Research Center, Islamic Azad University, Tehran, Iran

It is a great pleasure to receive your message regarding the acceptance of our manuscript for publication in EPJPlus. We deeply appreciate the quick review of the manuscript and sincerely thank you and others in the EPJP Editorial Office. We would also like to extend our appreciation to the referee for his positive review and his nice words.

Kourosh Afrousheh, Safat, Kuwait

I would like to thank the Editors for the effective editorial procedures and I would also like to thank the Copy Editors for their meticulous work.

Ahmet Baykal, Nigde University, Turkey

The authors acknowledge the two anonymous reviewers for the constructive comments and suggestions which have helped to improve the manuscript significantly and thank the journal for the kind collaboration.

Sandra Morelli, Università di Modena, Italy