<!DOCTYPE AAA [
<!ELEMENT AAA (BBB+)>
<!ELEMENT BBB EMPTY>
<!ATTLIST BBB ident ID #REQUIRED>
]>
<AAA>
  <BBB ident="aap" />
  <BBB ident="noot" />
  <BBB ident="mies" />
  <BBB ident="boom" />
  <BBB ident="roos" />
</AAA> 
