1. R. Bowen, Topological entropy and Axiom A,Proc. Symp. Pure Math., A.M.S., Providence R.I.,14 (1970), 23–41.
2. R. Bowen, Periodic points and measures for Axiom A diffeomorphisms,Trans. Amer. Math. Soc.,154 (1971). 377–397.
3. R. Bowen, Periodic orbits for hyperbolic flows,Amer. J. Math.,94 (1972), 1–30.
4. D. V. Anosov, On certain class of invariant sets of smooth dynamical systems (in Russian),Proc. 5th International Conf. on Non-linear Oscillations, vol. 2, Kiev, 1970, 39–45.
5. A. B. Katok, Dynamical systems with hyperbolic structure (in Russian),Ninth Summer Math. School, Kier, published by Math. Inst. of the Ukrainian Acad. of Sci., 1972; revised edition Kiev, Naukova Dumka, 1976, 125–211; to be translated into English.