<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

 <xs:element name="library">

  <xs:complexType>

   <xs:sequence>

    <xs:element name="book" maxOccurs="unbounded">

     <xs:complexType>

      <xs:sequence>

       <xs:element name="isbn" type="xs:integer"/>

       <xs:element name="title">

        <xs:complexType>

         <xs:simpleContent>

          <xs:extension base="xs:string">

           <xs:attribute name="lang" type="xs:language"/>

          </xs:extension>

         </xs:simpleContent>

        </xs:complexType>

       </xs:element>

       <xs:element name="author" minOccurs="0" maxOccurs="unbounded">

        <xs:complexType>

         <xs:sequence>

          <xs:element name="name" type="xs:string"/>

          <xs:element name="born" type="xs:date"/>

          <xs:element name="dead" type="xs:date"/>

         </xs:sequence>

         <xs:attribute name="id" type="xs:ID"/>

        </xs:complexType>

       </xs:element>

       <xs:element name="character" minOccurs="0" maxOccurs="unbounded">

        <xs:complexType>

         <xs:sequence>

          <xs:element name="name" type="xs:string"/>

          <xs:element name="born" type="xs:date"/>

          <xs:element name="qualification" type="xs:string"/>

         </xs:sequence>

         <xs:attribute name="id" type="xs:ID"/>

        </xs:complexType>

       </xs:element>

      </xs:sequence>

      <xs:attribute name="id" type="xs:ID"/>

      <xs:attribute name="available" type="xs:boolean"/>

     </xs:complexType>

    </xs:element>

   </xs:sequence>

  </xs:complexType>

 </xs:element>

</xs:schema>