Extend DTD with more HTML subset

xep.dtd

@@ -88,7 +88,7 @@ THE SOFTWARE.
 <!ATTLIST section5
           topic CDATA ''
           anchor CDATA '' >
-<!ELEMENT div ( div | p | example | code | ul | ol | dl | table | blockquote )* >
+<!ELEMENT div ( #PCDATA | div | p | example | code | ul | ol | dl | table | blockquote )* >
 <!ATTLIST div
           class CDATA ''
           style CDATA '' >
@@ -124,7 +124,7 @@ THE SOFTWARE.
 <!ELEMENT link (#PCDATA | cite)* >
 <!ATTLIST link url CDATA '' >
 <!ELEMENT note (#PCDATA | link | tt | dfn | em | strong | cite | span | note)* >
-<!ELEMENT blockquote (#PCDATA)* >
+<!ELEMENT blockquote (#PCDATA | blockquote)* >
 <!ELEMENT acronym (#PCDATA)* >
 <!ELEMENT example (#PCDATA)* >
 <!ATTLIST example caption CDATA '' >