Zhang, D., X. Ju, W. Zhang, J. Li, S. Li, Q. Zhu, and G. Zhou. “Multi-Modal Multi-Label Emotion Recognition With Heterogeneous Hierarchical Message Passing”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 35, no. 16, May 2021, pp. 14338-46, doi:10.1609/aaai.v35i16.17686.