2021 BEETL Competition: Advancing Transfer Learning for Subject Independence & Heterogenous EEG Data Sets. - Xiaoxi Wei; A. Aldo Faisal; Moritz Grosse-Wentrup; Alexandre Gramfort; Sylvain Chevallier; Vinay Jayaram; Camille Jeunet; Stylianos Bakas; Siegfried Ludwig; Konstantinos Barmpas; Mehdi Bahri; Yannis Panagakis; et al. (NeurIPS (Competition and Demos), 2021)