Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/xml-1.1/not-wf/P77/ibm77n04.xml
<?xml version='1.1'?> <!DOCTYPE doc [ <!ELEMENT doc (#PCDATA)> <!ENTITY e SYSTEM "ibm77n04.ent"> ]> <doc>&e;</doc>