Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/invalid/P68/ibm68i01.dtd
<!ENTITY ge1 "abcdef"> <!ELEMENT a EMPTY> <!ATTLIST a attr1 CDATA "&ge2;"> <!--* GE reference therebefore doesn't match declaration *-->