1. F. Behrend. On sets of integers which contain no three terms in arithmetic progression, Proc. Nat. Acad. Sci., 32:331–332, 1946
2. M. Elkin, An improved construction of progression-free sets, available at
http://arxiv.org/abs/0801.4310
3. R. Graham, On the growth of a van der Waerden-like function, Integers, 6:#A29, 2006
4. B. Landman, A. Robertson and C. Culver, Some new exact van der Waerden numbers, Integers, 5(2):#A10, 2005