1. I. P. Cornfeld, S. V. Forain and Ya. G. Sinai, Ergodic Theory. Springer-Verlag, Berlin and New York, 1982.
2. C. Dellacherie and P.-A. Meyer, Probabilités et potentiel, Partie B: Théorie des martingales. Hermann, Paris, 1980.
3. J. L. Doob, Stochastic Processes. Wiley, New York, 1953.
4. N. Dunford and J. T. Schwartz, Linear Operators, Part I: General Theory. WileyInterscience, New York, 1958.
5. D. A. Edwards, A maximal ergodic theorem for Abel means. J. Functional Anal. 7(1971), 61–70.