Blended Learning: Educational Innovation for Personalized Learning 12th International Conference, ICBL 2019, Hradec Kralove, Czech Republic, July 2-4, 2019, Proceedings - Cheung, Simon K. S.; Cheung, Simon K. S.; Lee, Lap-Kei; Lee, Lap-Kei; Simonova, Ivana; Simonova, Ivana; Kozel, Tomas; Kozel, Tomas; Kwok, Lam-For; Kwok, Lam-For (Springer International Publishing : Imprint: Springer, 2019)