%0 Journal Article %A A. Eduardo Gatto %A %T On Sobolev spaces of fractional order and ε-families of operators on spaces of homogeneous type %J Studia Mathematica %D 1999 %P 19-27 %V 133 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/sm-133-1-19-27/ %R 10.4064/sm-133-1-19-27 %G en %F 10_4064_sm_133_1_19_27