International Conference on Education and Social Sciences - INTCESS 2019. medzinárodná konferencia. 6th International Conference on Education and Social Science - INTCESS 2019 : abstracts & proceedings [elektronický zdroj]. 1. vyd. Istanbul : International Organization Center of Academic Research, 2019. Available on Internet: <http://www.ocerints.org/intcess19_e-publication/> ISBN 978-605-82433-5-4.