<include href="filter_sru_z3950.rng"/>
<include href="filter_virt_db.rng"/>
<include href="filter_z3950_client.rng"/>
+ <include href="filter_zoom.rng"/>
<define name="any">
<zeroOrMore>
<choice>
<ref name="filter_sru_z3950"/>
<ref name="filter_virt_db"/>
<ref name="filter_z3950_client"/>
+ <ref name="filter_zoom"/>
</choice>
</element>
</define>