1. Minimal Flows and Their Extensions;Auslander,1988
2. Lectures on Topological Dynamics;Ellis,1969
3. Almost periodicity, equi-continuity and total boundedness;Gottschalk;Bull. Amer. Math. Soc.,1946
4. Almost periodic points with respect to transformation semi-groups;Gottschalk;Ann. Math.,1946
5. Topological Dynamics;Gottschalk,1955