[1] Z. Šidák: Eigenvalues of operators in denumerable Markov chains. Trans. 3rd Prague Conf. on Inf. Theory, Stat. Dec. Functions, Random Proc. held in 1962, Prague 1964, pp. 641-656. MR 0192560

[2] Z. Šidák: Eigenvalues of operators in $l\sb p$-spaces in denumerable Markov chains. Czech. Math. J. 14 (89) (1964), pp. 438-443. MR 0176527

[3] Z. Šidák: Classification of Markov chains with a general state space. (Research announcement.) Bull. Amer. Math. Soc. 72, No. 1 (January 1966). MR 0185705

[4] Z. Šidák: Classification of Markov chains with a general state space. Trans. 4th Prague Conf. on Inf. Theory, Stat. Dec. Functions, Random Proc. held in Prague 1965 (in print). MR 0185705