testing/xml-testsuite/src/main/resources/org/apache/axiom/ts/xml/entity-reference-nested.xml

<?xml version="1.0"?>
<!DOCTYPE root [
  <!ENTITY ref1 "A &ref2; C">
  <!ENTITY ref2 "B">
  <!ELEMENT root (#PCDATA)>
]>
<root>
    &ref1;
</root>