Dear Sabine,
For me it was a great pleasure to work with you, Christian and Isabelle. All questions have been resolved very fast. And amiability and competence of Isabelle are inestimable. Best regards,

Natasha Kirova, CNRS & University Paris Sud, Orsay, France
Editor EPJ Special Topics 222/5, 2013

Dear Isabelle,
Many thanks for the hard work indeed! The entire volume and the cover look really very good, thanks again.

George Kampis, Collegium Budapest, Hungary
Editor EPJ Special Topics 222/6, 2013

Dear Isabelle,
Many thanks for all the hard work. Many thanks indeed!

Peter M.A. Sloot, University of Amsterdam, The Netherlands
Editor EPJ Special Topics 222/6, 2013

Thank you very much, Isabelle! Very timely. And the cover looks fantastic! We are grateful for the great collaboration! Best wishes.

Dirk Helbing, ETH Zurich, Switzerland
Editor EPJ Special Topics 214, 2012

We thank you very much for the confidence, the work done, the speed and the various orientations for its successful completion. We also take the opportunity to thank your team for their open-mindedness.

Arnaud Edouard Yamadjako, University of Abomey-Calavi, Godomey, Benin

It was a beautiful experience publishing with EPJP. Finally, thank you very much for your kind consideration and also many thanks to the EPJP peer review team.

Muhammad Riaz, University of the Punjab, Lahore, Pakistan

We would like to thank the referee for very good and well intended remarks which helped us to improve our manuscript.

Marina-Aura Dariescu, "Alexandru Ioan Cuza" University of Iasi, Romania

The typing and the arrangement of tables and figures are perfect. Also, corrections to English and bibliography were appropriate. All together there is no correction to be made and I thank you for the excellent work. I would also thank you for the kind promptness in delivering the proofs.

Maurizio Consoli, Istituto Nazionale di Fisica Nucleare - Sezione di Catania, Italy

Thank you. We are indebted to the reviewers, Editor for their time and pinpoint comments and suggestions. I am also thankful for the Editorial office. The speed of the manuscript processing and the updates are too good.

Vemula Ramakrishna Reddy, IIT Hyderabad, India

I wish to congratulate the production staff for the precision in reproducing the text and the equations and formulas. It is not so frequent, nowadays.

Loris Ferrari, Università di Bologna, Italy