CBU International Conference Proceedings 2019. Innovations in Science and Education. CBU International Conference Proceedings 2019 : Innovations in Science and Education. Vol. 7. 1st Edition. Prague : CBU Research Institute, 2019. [1025] s. Available on Internet: <https://ojs.journals.cz/index.php/CBUIC/article/view/1501/2034> ISBN 978-80-907722-0-5. ISSN 1805-997X.