%0 Journal Article %A K. Bhaskara Rao %A R. Shortt %T On systems of null sets %J Colloquium Mathematicum %D 1999 %P 1-4 %V 81 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-81-1-1-4/ %R 10.4064/cm-81-1-1-4 %G en %F 10_4064_cm_81_1_1_4