REACT2023: The First Multiple Appropriate Facial Reaction Generation Challenge. - Song, Siyang; Spitale, Micol; Luo, Cheng; Barquero, Germán; Palmero, Cristina; Escalera, Sergio; Valstar, Michel F.; Baur, Tobias; Ringeval, Fabien; André, Elisabeth; Gunes, Hatice (2023)