Hou, Wentai, et al. “H^2-MIL: Exploring Hierarchical Representation With Heterogeneous Multiple Instance Learning for Whole Slide Image Analysis”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 36, no. 1, June 2022, pp. 933-41, doi:10.1609/aaai.v36i1.19976.