Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/not-wf/P14/ibm14n01.xml
<?xml version="1.0"?> <!DOCTYPE student [ <!ELEMENT student (#PCDATA)> <!ATTLIST student first CDATA #REQUIRED last CDATA #IMPLIED> ]> <!-- testing invalid chardata string --> <student first="Snow">My name is Snow ]]> Man</student>