<xs:element name="indexterm">
    <xs:complexType>
        <xs:sequence>
            <xs:element minOccurs="0" ref="docbook:primary" />
            <xs:choice minOccurs="0">
                <xs:sequence>
                    <xs:element ref="docbook:secondary" />
                    <xs:choice minOccurs="0">
                        <xs:sequence>
                            <xs:element ref="docbook:tertiary" />
                            <xs:choice minOccurs="0">
                                <xs:element ref="docbook:see" />
                                <xs:element maxOccurs="unbounded" ref="docbook:seealso" />
                            </xs:choice>
                        </xs:sequence>
                        <xs:element ref="docbook:see" />
                        <xs:element maxOccurs="unbounded" ref="docbook:seealso" />
                    </xs:choice>
                </xs:sequence>
                <xs:element ref="docbook:see" />
                <xs:element maxOccurs="unbounded" ref="docbook:seealso" />
            </xs:choice>
        </xs:sequence>
        <xs:attribute name="role" />
        <xs:attributeGroup ref="docbook:db.common.attributes" />
        <xs:attributeGroup ref="docbook:db.common.linking.attributes" />
        <xs:attribute name="significance">
            <xs:simpleType>
                <xs:restriction base="xs:token">
                    <xs:enumeration value="normal" />
                    <xs:enumeration value="preferred" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="startref" type="xs:IDREF" />
        <xs:attribute name="zone" type="xs:IDREFS" />
        <xs:attribute name="pagenum" />
        <xs:attribute name="scope">
            <xs:simpleType>
                <xs:restriction base="xs:token">
                    <xs:enumeration value="all" />
                    <xs:enumeration value="global" />
                    <xs:enumeration value="local" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="type" />
        <xs:attribute name="class">
            <xs:simpleType>
                <xs:restriction base="xs:token">
                    <xs:enumeration value="singular" />
                    <xs:enumeration value="startofrange" />
                    <xs:enumeration value="endofrange" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
    </xs:complexType>
</xs:element>