<xs:element name="CouponInfo" maxOccurs="16">
    <xs:annotation>
        <xs:documentation xml:lang="en">Identifies the coupon to be used to check-in for a flight segment or segments. </xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:attribute name="FlightRPH" type="ListOfRPH" use="required">
            <xs:annotation>
                <xs:documentation xml:lang="en">A reference place holder used as a pointer to link back to the flight.</xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="CouponNumber" type="Numeric1to4" use="required">
            <xs:annotation>
                <xs:documentation xml:lang="en">The coupon number.</xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="DocumentNumberCheckDigit" use="optional">
            <xs:annotation>
                <xs:documentation xml:lang="en">The number calculated by the check digit routine. </xs:documentation>
            </xs:annotation>
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:pattern value="[0-9]{1}" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="PaperTicketInd" type="xs:boolean" use="optional">
            <xs:annotation>
                <xs:documentation xml:lang="en">Indicates whether passenger is using a paper ticket for this segment. If true, passenger is using a paper ticket to check-in for this segment. If false or unpopulated, the passenger is using an electronic ticket for this segment. </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="CouponReference" type="AlphaNumericStringLength1to8" use="optional">
            <xs:annotation>
                <xs:documentation xml:lang="en">Coupon number, relative to total number of coupons (e.g., 10 of 12)</xs:documentation>
            </xs:annotation>
        </xs:attribute>
    </xs:complexType>
</xs:element>