<xs:element name="catalog">
    <xs:annotation>
        <xs:documentation>A local or remote catalog.</xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:sequence>
            <xs:element ref="title" minOccurs="0" maxOccurs="unbounded">
                <xs:annotation>
                    <xs:documentation>A short natural language name for the Catalog.</xs:documentation>
                </xs:annotation>
            </xs:element>
            <xs:element name="scheme" maxOccurs="unbounded">
                <xs:annotation>
                    <xs:documentation>A scheme alias-to-URI mapping.</xs:documentation>
                </xs:annotation>
                <xs:complexType>
                    <xs:attribute name="alias" type="xs:NCName" use="required">
                        <xs:annotation>
                            <xs:documentation>A short string used by the provider as a replacement for a scheme URI.</xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:attribute name="uri" type="IRIType" use="required">
                        <xs:annotation>
                            <xs:documentation>The URI which identifies the scheme.</xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:anyAttribute namespace="##other" processContents="lax" />
                </xs:complexType>
            </xs:element>
        </xs:sequence>
        <xs:attribute name="additionalInfo" type="IRIType">
            <xs:annotation>
                <xs:documentation>A pointer to some additional information about the Catalog, and especially its evolution and latest version.</xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:anyAttribute namespace="##other" processContents="lax" />
        <!-- EV-NAR-1.3.7: add @additionalInfo to catalog-->
    </xs:complexType>
</xs:element>