%0 Journal Article %A Ranzato, F. %T A counterexample to a result concerning closure operators. %J Portugaliae mathematica %D 2001 %P 121-125 %V 58 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/PORMA_2001__58_1_49581/ %G en %F PORMA_2001__58_1_49581