/ libxml2 / test / valid / t10.xml
t10.xml
 1  <?xml version="1.0" standalone="yes"?>
 2  <!DOCTYPE root [
 3  <!ELEMENT root  (cont1, (cont1, cont2?)+)>
 4    <!ELEMENT cont1  EMPTY>
 5    <!ELEMENT cont2  EMPTY>
 6  ]>
 7  <root>
 8    <cont1/>
 9    <cont1/>
10    <cont1/>
11    <cont1/>
12  </root>