<!DOCTYPE shref [
  <!ELEMENT shref - - (netc|twit|twat)*>
  <!ELEMENT netc  - - (frob+)>
  <!ELEMENT frob  O O (twit)>
  <!ELEMENT twit  - O (#PCDATA)>
  <!ELEMENT twat  - - CDATA>
]>    
<shref>
<netc/<frob><twit>This slash should end netc:/
<twat/This is a twat/
<twit/This is a simple shortref/
</shref>
