1<grammar xmlns="http://relaxng.org/ns/structure/1.0">
2  <start>
3    <ref name="head"/>
4  </start>
5  <define name="head">
6    <element name="head">
7      <interleave>
8        <ref name="title"/>
9        <optional>
10          <ref name="base"/>
11        </optional>
12        <zeroOrMore>
13          <ref name="style"/>
14        </zeroOrMore>
15        <zeroOrMore>
16          <ref name="script"/>
17        </zeroOrMore>
18        <zeroOrMore>
19          <ref name="link"/>
20        </zeroOrMore>
21        <zeroOrMore>
22          <ref name="meta"/>
23        </zeroOrMore>
24      </interleave>
25    </element>
26  </define>
27  <define name="title">
28    <element name="title">
29      <text/>
30    </element>
31  </define>
32  <define name="base">
33    <element name="base">
34      <text/>
35    </element>
36  </define>
37  <define name="style">
38    <element name="style">
39      <text/>
40    </element>
41  </define>
42  <define name="script">
43    <element name="script">
44      <text/>
45    </element>
46  </define>
47  <define name="meta">
48    <element name="meta">
49      <text/>
50    </element>
51  </define>
52  <define name="link">
53    <element name="link">
54      <text/>
55    </element>
56  </define>
57</grammar>
58