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Language: English
Page range: 57 - 60
Submitted on: Oct 30, 2016
Accepted on: Jan 11, 2017
Published on: Feb 9, 2017
Published by: Konstantin Preslavski University of Shumen
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
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© 2017 P. Petkova, P. Vasilev, B. Bedzhev, R. Belcheva, published by Konstantin Preslavski University of Shumen
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.