1. C. Berge, Graphes et Hypergraphes, Dunod, Paris, 1970
2. B. Lindström, A Theorem on families of Sets, J. of Combinatorial Theory, A. 13, 1972, 274–277.
3. P. Erdös, Chao Ko, R. Rado, Intersection theorems for systems of finite sets, Quart. J. of Math. (Oxford) (2) 12 (1961), 313–320.
4. E. Lucas, Récréations Mathématiques, A. Blanchard, Paris, 1892–1924.
5. R. Peltesohn, Das Turnier Problem für Spiele zu je dreier, Inaugural Dissertation, Friedrich-Wilhelms-Universität zu Berlin 1936.