A big issue of 2020?
Vol.30,No.2(2020)

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Copyright © 2020 Petr Najvar, Eva Minaříková
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Copyright © 2020 Petr Najvar, Eva Minaříková