Ferns N., Panangaden, P., & Precup, D. (2004) Metrics for finite Markov decision processes Proceedings of the 20th conference on Uncertainty in artificiall intelligence.
Ferns N., Panangaden, P., & Precup, D. (2005) Metrics for Markov decision processes with infinite state spaces Proceedings of the 20th conference on Uncertainty in artificiall intelligence.
Ferns N., Castro, P., Precup, D., & Panangaden, P. Methods for Computing State Similarity in Markov Decision Processes.