Li, M., S. Zhang, F. Zhu, W. Qian, L. Zang, J. Han, and S. Hu. “Symmetric Metric Learning With Adaptive Margin for Recommendation”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 34, no. 04, Apr. 2020, pp. 4634-41, doi:10.1609/aaai.v34i04.5894.