Advances in information retrieval 42nd European Conference on IR Research, ECIR 2020, Lisbon, Portugal, April 14–17, 2020 : proceedings, part I - Jose, Joemon M.; Yilmaz, Emine; Magalhães, João; Castells, Pablo; Ferro, Nicola; Silva, Mário J.; Martins, Flávio (Lecture notes in computer science, 2020)