1. Every group admits a bad topology;Ajtai,1983
2. Minimal Flows and their Extensions;Auslander,1988
3. A semigroup associated with a transformation group;Ellis;Trans. Amer. Math. Soc.,1960
4. Lectures in Topological Dynamics;Ellis,1969
5. Recurrence in Ergodic Theory and Combinatorial Number Theory;Furstenberg,1981