[1] J. BALATONI A. RÉNYI: On the notion of entropy. (Hungarian), Publ. Math. Inst. Hungarian Acad. Sci. 1 (1956), 9-40. - English translation: Selected papers of Alfred Rényi, vol. I, pp. 558-584, Akademiat Kiado, Budapest, 1976.

[2] M. KATĚTOV: Extended Shannon entropies I. Czechosl. Math. J. 33 (108) (1983), 564-601. MR 0721088

[3] M. KATĚTOV: On extended Shannon entropies and the epsilon entropy. Comment. Math. Univ. Carolinae 27 (1986), 519-534. MR 0873625

[4] A. RÉNYI: On the dimension and entropy of probability distributions. Acta Math. Acad. Sci. Hung. 10 (1959), 193-215. MR 0107575

[5] A. RÉNYI: Dimension, entropy and information. Trans. 2nd Prague Conf. Information Theory, pp. 545-556. Prague, 1960. MR 0129049

[6] A. RÉNYI J. BALATONI: Über den Begriff der Entropie, Arbeiten zur Informationstheorie. pp. 117-134. Deutscher Verlag der Wissenschaften, Berlin, 1957.