[1] B. Balcar P. Kalášek S. W. Williams: On the multiple Birkhoff recurrence theorem in dynamics. Comment. Math. Univ. Carolinae 28 (1987), 607-612. MR 0928675

[2] W. W. Comfort S. Negrepontis: The theory of ultrafilters. Springer-Verlag, Heidelberg, 1974. MR 0396267

[3] R. Engelking: General Topology. Warszawa PWN, 1977. MR 0500780 | Zbl 0373.54002

[4] H. Furstenberg: Ergodic behaviour of diagonal measures and a theorem of Szemeredi on arithmetic progressions. J. d'Analyse Math. 31 (1977), 204-256. MR 0498471

[5] H. Furstenberg: Recurrence in ergodic theory and combinatorial number theory. Princeton University Press, New Jersey, 1981. MR 0603625 | Zbl 0459.28023

[6] H. Furstenberg B. Weiss: Topological dynamics and combinatorial number theory. J. d'Analyse Math. 34 (1978), 61-85. MR 0531271

[7] R. L. Graham B. L. Ritschild J. H. Spencer: Ramsey theory. J. Wiley and Sons, New York, 1980. MR 0591457