Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/valid/P61/ibm61v01.xml
<?xml version="1.0"?> <!-- syntax test for Production 61--> <!DOCTYPE animal SYSTEM "ibm61v01.dtd"> <animal> <tiger/> </animal>