%0 Journal Article %A Colin C. Graham %A Thomas Ramsey %T Three results on I-sets %J Colloquium Mathematicum %D 1987 %P 141-147 %V 51 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-51-1-141-147/ %R 10.4064/cm-51-1-141-147 %G en %F 10_4064_cm_51_1_141_147