%0 Journal Article %A E. Fabes %A N. Garofalo %A S. Salsa %T A control on the set where a Green's function vanishes %J Colloquium Mathematicum %D 1990 %P 637-647 %V 60 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-60-61-2-637-647/ %R 10.4064/cm-60-61-2-637-647 %G en %F 10_4064_cm_60_61_2_637_647