removing hardcoded link in summary of authority (on $heading) : it can be set in the template (in the # of biblios column) :
<a href="/cgi-bin/koha/opac-search.pl?type=opac&op=do_search&marclist=<!-- TMPL_VAR NAME="biblio_fields" -->&operator==&value=<!-- TMPL_VAR NAME="authid" -->&and_or=and&excluding="><!-- TMPL_VAR NAME="used" --></a> <!-- TMPL_VAR NAME="used" -->
that's what I did for css templates, it work like a charm. It's better I think because when the library defines it's own summary, the hardcoded link didn't appear.