1. G. D. Birkhoff and P. A. Smith. Structure Analysis of Surface Transformations, Journ. de. Math. Tome VII — Fasc IV, (1928), 345–379, Birkhoff: Collected Mathematical Papers, Vol. 2, 360–394, Dover,1968.
2. P. Chaube and M. G. Nadkarni. On Orbit Equivalence of Borel Automorphisms, Proc. Indian Acad Sci. (Math. Sci.), 99 (1989), 255–261.
3. S. Eigen, A. Hajian and M. G. Nadkarni. Weakly Wandering Sets and Compressibility in Descriptive Setting. Proc. Indian Acad. Sci. (Math. Sci.), 103 (1993), 321–327.
4. A. B. Hajian and S. Kakutani. Weakly Wandering Sets and Invariant Measures, Trans. Amer. Math. Soc., 110 (1964), 136–151.
5. E. Hopf. Theory of Measures and Invariant Integrals, Trans. Amer. Math. Soc., 34 (1932), 373–393.