COVID-19 Literature Topic-Based Search via Hierarchical NMF Rachel Grotheer author Longxiu Huang author Yihuan Huang author Alona Kryshchenko author Oleksandr Kryshchenko author Pengyu Li author Xia Li author Elizaveta Rebrova author Kyung Ha author Deanna Needell author 2020-12 text Proceedings of the 1st Workshop on NLP for COVID-19 (Part 2) at EMNLP 2020 Karin Verspoor editor Kevin Bretonnel Cohen editor Michael Conway editor Berry de Bruijn editor Mark Dredze editor Rada Mihalcea editor Byron Wallace editor Association for Computational Linguistics Online conference publication grotheer-etal-2020-covid 10.18653/v1/2020.nlpcovid19-2.4 https://aclanthology.org/2020.nlpcovid19-2.4/ 2020-12