<attribute name="relativePosition">
    <simpleType>
        <restriction base="string">
            <enumeration value="Before" />
            <enumeration value="After" />
            <enumeration value="Begins" />
            <enumeration value="Ends" />
            <enumeration value="During" />
            <enumeration value="Equals" />
            <enumeration value="Contains" />
            <enumeration value="Overlaps" />
            <enumeration value="Meets" />
            <enumeration value="OverlappedBy" />
            <enumeration value="MetBy" />
            <enumeration value="BegunBy" />
            <enumeration value="EndedBy" />
        </restriction>
    </simpleType>
</attribute>