<?xml version="1.0" encoding="iso-8859-1"?>
-<!ELEMENT publication (title,author+,where)>
+<!ELEMENT publication (title,author*,where,html?)>
<!ELEMENT title (#PCDATA)>
<!-- name,surname must be provided iff the "file" attribute is not provided -->
<!ELEMENT where (#PCDATA)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT surname (#PCDATA)>
+
+<!ELEMENT html EMPTY>
+<!ATTLIST html
+ file CDATA #REQUIRED>