<?xml version='1.0'?>
<!DOCTYPE root [
<!ENTITY % deftest '<!ELEMENT test (#PCDATA) >' >
<!ENTITY % defmiddle '<!ELEMENT middle (test) >' >
<!ENTITY % defroot '<!ELEMENT root (middle) >' >
%defroot; %defmiddle; %deftest;
]>
<root><middle><test>sample</test></middle></root>