Perspectives of System Informatics 12th International Andrei P. Ershov Informatics Conference, PSI 2019, Novosibirsk, Russia, July 2-5, 2019, Revised Selected Papers - Bjørner, Nikolaj; Bjørner, Nikolaj; Virbitskaite, Irina; Virbitskaite, Irina; Voronkov, Andrei; Voronkov, Andrei (Springer International Publishing : Imprint: Springer, 2019)