IST-Unbabel 2021 Submission for the Explainable Quality Estimation Shared Task Marcos Treviso author Nuno M Guerreiro author Ricardo Rei author André F T Martins author 2021-11 text Proceedings of the 2nd Workshop on Evaluation and Comparison of NLP Systems Yang Gao editor Steffen Eger editor Wei Zhao editor Piyawat Lertvittayakumjorn editor Marina Fomicheva editor Association for Computational Linguistics Punta Cana, Dominican Republic conference publication treviso-etal-2021-ist 10.18653/v1/2021.eval4nlp-1.14 https://aclanthology.org/2021.eval4nlp-1.14/ 2021-11 133 145