@article{KellerRoellyValleriani2015,
  author    = {Peter Keller and Sylvie Roelly and Angelo Valleriani},
  title     = {On time duality for Markov Chains},
  journal   = {Stochastic models},
  volume    = {31},
  number    = {1},
  pages     = {98 -- 118},
  doi       = {10.1080/15326349.2014.969736},
  year      = {2015},
}