Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/valid/P57/out/ibm57v01.xml
<!DOCTYPE root [ <!NOTATION a SYSTEM 'a'> <!NOTATION b SYSTEM 'b'> ]> <root> This test case tests the kinds of enumerated types <a></a><b></b> </root>