R. McCutcheon IP<sub><i>r</i></sub> sets with polynomial weights and Szemerédi's theorem. 167-174 2007 114 J. Comb. Theory, Ser. A 1 http://dx.doi.org/10.1016/j.jcta.2006.02.004 db/journals/jct/jcta114.html#McCutcheon07