1. J. L. Doob, Stochastic Processes, p. 153, J. Wiley, New York.
2. A Course in Probability Theory;Chung,1974
3. Introduction to Stochastic Control;Kushner,1971
4. Maximum likelihood sequence estimation of digital sequences in the presence of intersymbol interference;Forney;IEEE Trans. Inform. Theory,1973
5. Error bounds for convolutional codes and an asymptotically optimum decoding algorithm;Viterbi;IEEE Trans. Inform. Theory,1967