Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/valid/P09/ibm09v02.xml
<?xml version="1.0"?> <!DOCTYPE student [ <!ELEMENT student (#PCDATA)> <!ENTITY FullName "SnowMan"> ]> <student>My Name is &FullName;. </student>