Heterogeneous Data Management, Polystores, and Analytics for Healthcare : VLDB Workshops, Poly 2021 and DMAH 2021, Virtual Event, August 20, 2021, Revised Selected Papers - Rezig, El Kindi; Dubovitskaya, Alevtina; Gadepally, Vijay; Kong, Jun; Kraska, Tim; Luo, Gang; Mattson, Timothy; Stonebraker, Michael; Wang, Fusheng (Cham Springer International Publishing AG, 2021)