The Semantic Web : 18th International Conference, ESWC 2021, Virtual Event, June 6-10, 2021, Proceedings - Verborgh, Ruben; Alam, Mehwish; Champin, Pierre-Antoine; Corcho, Oscar; Hose, Katja; Maleshkova, Maria; Paulheim, Heiko; Ristoski, Petar (Springer International Publishing, 2021)