<xsd:element name="keyword">
  <xsd:annotation>
    <xsd:documentation>
      <type>Element</type>
      <name>keyword</name>
      <comment>The element keyword is a metadata element specifying a keyword associated to the FRBR expression of the document. Attribute dictionary (required) specifies the thesaurus out of which the keyword has been taken. Attribute href points to the fragment of text this keyword is associated to. Keywords without href attribute refer to the content as a whole.</comment>
    </xsd:documentation>
  </xsd:annotation>
  <xsd:complexType>
    <xsd:complexContent>
      <xsd:extension base="metaopt">
        <xsd:attributeGroup ref="linkopt"/>
        <xsd:attributeGroup ref="value"/>
        <xsd:attributeGroup ref="show"/>
        <xsd:attribute name="dictionary" type="xsd:anyURI" use="required"/>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>
</xsd:element>

<xsd:attribute name="dictionary" type="xsd:anyURI" use="required"/>