Published Online: Dec 22, 2018
Page range: 245 - 250
DOI: https://doi.org/10.2478/mgrsd-1988-030130
© 2018 Marta Piasecka, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.
Marta Piasecka