Database and Expert Systems Applications 30th International Conference, DEXA 2019, Linz, Austria, August 26-29, 2019, Proceedings, Part II - Hartmann, Sven; Hartmann, Sven; Küng, Josef; Küng, Josef; Chakravarthy, Sharma; Chakravarthy, Sharma; Anderst-Kotsis, Gabriele; Anderst-Kotsis, Gabriele; Tjoa, A Min; Tjoa, A Min; Khalil, Ismail; Khalil, Ismail (Springer International Publishing : Imprint: Springer, 2019)