Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/not-wf/P62/ibm62n07.xml
<?xml version="1.0"?> <!-- syntax test for Production 62--> <!DOCTYPE animal SYSTEM "ibm62n07.dtd"> <animal> <tiger/> Negative test. Missing closing sequence. </animal>