Han, Fei, Hua Wang, and Hao Zhang. “Learning Integrated Holism-Landmark Representations for Long-Term Loop Closure Detection”. Proceedings of the AAAI Conference on Artificial Intelligence 32, no. 1 (April 26, 2018). Accessed October 24, 2021. https://ojs.aaai.org/index.php/AAAI/article/view/12101.