<xsd:group name="markerElements"><xsd:annotation><xsd:documentation><type>Group</type><name>markerElements</name><comment>The group markerElements lists all the elements that are markers</comment></xsd:documentation></xsd:annotation><xsd:choice><xsd:group ref="ANmarker"/><xsd:group ref="HTMLmarker"/><xsd:element ref="marker"/></xsd:choice></xsd:group>