1. Aigner, M., Ziegler, G.M.: Proofs from THE BOOK, 4th edn. Springer, Berlin, New York (2009)
2. Alon, N.: Discrete mathematics: methods and challenges. In: Proceedings of the International Congress of Mathematicians, Beijing, 2002, vol. 1, pp. 119–135. Higher Ed. Press, Beijing (2002)
3. Bamberg, J., de Clerck, F., Durante, N.: Intriguing sets in partial quadrangles. J. Comb. Des. 19, 217–245 (2011)
4. Borsuk, K.: Three theorems on the n-dimensional sphere. Fundam. Math. 20, 177–190 (1933) (in German)
5. Brass, P., Moser, W., Pach, J.: Research Problems in Discrete Geometry. Springer, Berlin (2005)