Xi, Dongbo, et al. “Modelling of Bi-Directional Spatio-Temporal Dependence and Users’ Dynamic Preferences for Missing POI Check-In Identification”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 33, no. 01, July 2019, pp. 5458-65, doi:10.1609/aaai.v33i01.33015458.