@conference {395, title = {Overview of BioASQ Tasks 9a, 9b and Synergy in CLEF2021}, booktitle = {Proceedings of the 9th BioASQ Workshop A challenge on large-scale biomedical semantic indexing and question answering}, year = {2021}, url = {http://ceur-ws.org/Vol-2936/paper-10.pdf}, author = {Nentidis, Anastasios and Katsimpras, Georgios and Vandorou, Eirini and Krithara, Anastasia and Paliouras, Georgios} }