unfortunatelly, the code itself:
firts passes a call CLASS Paper
to select those entries in the keyset which
are paper by themselves
so a class Paper must be defined
i am a bit surprised though that ?Paper with a "-Rename Reference"
does not work
i think a way out is a subclass
define class Paper Hidden
define class Reference subclass of Paper filter
no filter or may be filter IS "*"
then the code should be happy