1. Blackwell P., An alternative proof of a theorem of Erdös and Szekeres.Amer. Math. Monthly 78 (1971), 273.
2. Bollobás B.,Extremal Graph Theory. Academic, London (1978).
3. Chvátal V., Some unknown van der Waerden numbers.Combinatorial Structures and Their Applications. Gordon & Breach (1970), 31–33.
4. Erdös P. andSzekeres G., A combinatorial problem in geometry.Compositio Math. 2 (1935), 463–470.
5. Graham R. L., Rothschild B., Spencer J.,Ramsey Theory. Wiley, New York (1981).