<grammar xmlns=“relaxng.org/ns/structure/1.0”>

<start>
  <ref name="head"/>
</start>
<define name="head">
  <element name="head">
    <interleave>
      <ref name="title"/>
      <optional>
        <ref name="base"/>
      </optional>
      <zeroOrMore>
        <ref name="style"/>
      </zeroOrMore>
      <zeroOrMore>
        <ref name="script"/>
      </zeroOrMore>
      <zeroOrMore>
        <ref name="link"/>
      </zeroOrMore>
      <zeroOrMore>
        <ref name="meta"/>
      </zeroOrMore>
    </interleave>
  </element>
</define>
<define name="title">
  <element name="title">
    <text/>
  </element>
</define>
<define name="base">
  <element name="base">
    <text/>
  </element>
</define>
<define name="style">
  <element name="style">
    <text/>
  </element>
</define>
<define name="script">
  <element name="script">
    <text/>
  </element>
</define>
<define name="meta">
  <element name="meta">
    <text/>
  </element>
</define>
<define name="link">
  <element name="link">
    <text/>
  </element>
</define>

</grammar>