Published Online: Dec 22, 2018
Page range: 139 - 142
DOI: https://doi.org/10.2478/mgrsd-1996-070120
© 2018 Hanna Cetnarska, Hanna Dziakowska, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.
Hanna Cetnarska
Hanna Dziakowska