test/xml2 - third_party/libxml2 - Git at Google

 <?xml version='1.0'?>
 <!DOCTYPE test [
 <!ELEMENT test (#PCDATA) >
 <!ENTITY % xx '&#37;zz;'>
 <!ENTITY % zz '&#60;!ENTITY tricky "error-prone" >' >
 %xx;
 ]>
 <test>This sample shows a &tricky; method.</test>
	<?xml version='1.0'?>
	<!DOCTYPE test [
	<!ELEMENT test (#PCDATA) >
	<!ENTITY % xx '%zz;'>
	<!ENTITY % zz '<!ENTITY tricky "error-prone" >' >
	%xx;
	]>
	<test>This sample shows a &tricky; method.</test>