%0 Journal Article %A Alex Hellsten %A Tapani Hyttinen %A Saharon Shelah %T Potential isomorphism and semi-proper trees %J Fundamenta Mathematicae %D 2002 %P 127-142 %V 175 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm175-2-3/ %R 10.4064/fm175-2-3 %G en %F 10_4064_fm175_2_3