@Book{karlin81,
  author =	 {Karlin, S and Taylor, H.M.},
  title = 	 {A second course in stochastic processes},
  publisher = 	 {Academic Press},
  year = 	 1981
}

@Book{norris97,
  author =	 {Norris, J. R},
  title = 	 {Markov Chains},
  publisher = 	 {Cambridge University Press},
  year = 	 1997
}