Holst, A., M. Bohlin, J. Ekman, O. Sellin, B. Lindström, and S. Larsen. “Statistical Anomaly Detection for Train Fleets”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 26, no. 2, July 2012, pp. 2217-23, doi:10.1609/aaai.v26i2.18961.