Hi, I designed a display of trees for hierarchical authorities. It is based on an analysis of authority records. It is mainly hard-coded. But could get adapted if need be. (And this avoids a big bunch of system preferences.) In my case, trees were to be found for subject authorities (main heading in field250). In UNIMARC, $3 subfield contains authority number, $5 contains a code that will tell you whether the field contains a broader term ($5==g) or a narrower term ($5==h). So let's take an example. 250$3 1212 $aEurope 550$3 1213 $5 g $aContinents 550$3 1214 $5 h $aFrance 550$3 1215 $5 h $aGermany 550$3 1216 $aNATO Will be displayed : Continents+ (Europe Asia America Africa...) (Continents) +Europe+ (France Germany) hierarchy.css contains the stylesheets for these facilities. So long. -- Henri-Damien LAURENT