<attributeGroup name="eventStateTennis">
    <attribute name="set" type="string" use="optional">
        <annotation>
            <documentation>An integer, 1,2,3,4,5.</documentation>
        </annotation>
    </attribute>
    <attribute name="game" type="string" use="optional">
        <annotation>
            <documentation>An integer, generally 1 through 7.</documentation>
        </annotation>
    </attribute>
    <attribute name="server-idref" type="IDREF" use="optional">
        <annotation>
            <documentation>A pointer to the player who served the ball on this point.</documentation>
        </annotation>
    </attribute>
    <attribute name="server-score" use="optional">
        <annotation>
            <documentation>Either love, 15, 30, 40, game.</documentation>
        </annotation>
        <simpleType>
            <restriction base="string">
                <enumeration value="love" />
                <enumeration value="15" />
                <enumeration value="30" />
                <enumeration value="40" />
                <enumeration value="game" />
            </restriction>
        </simpleType>
    </attribute>
    <attribute name="receiver-idref" type="IDREF" use="optional">
        <annotation>
            <documentation>A pointer to the player who received the served ball on this point.</documentation>
        </annotation>
    </attribute>
    <attribute name="receiver-score" use="optional">
        <annotation>
            <documentation>Either love, 15, 30, 40, game.</documentation>
        </annotation>
        <simpleType>
            <restriction base="string">
                <enumeration value="love" />
                <enumeration value="15" />
                <enumeration value="30" />
                <enumeration value="40" />
                <enumeration value="game" />
            </restriction>
        </simpleType>
    </attribute>
    <attribute name="serve-number" use="optional">
        <annotation>
            <documentation>Identifying either the first or second serve.</documentation>
        </annotation>
        <simpleType>
            <restriction base="string">
                <enumeration value="first" />
                <enumeration value="second" />
            </restriction>
        </simpleType>
    </attribute>
</attributeGroup>