Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/xmltest/not-wf/sa/186.xml

<!DOCTYPE a [
<!ELEMENT a EMPTY>
<!ATTLIST a b CDATA #IMPLIED d CDATA #IMPLIED>
]>
<a b="c"d="e"/>