nEspecificando atributos dos elementos
n<!ATTRLIST (chapter|section) id CDATA
#IMPLIED>
n<!ATTRLIST reference id CDATA #REQUIRED
type (section|page)
section>
nUsando
n<chapter id=“sgml”>
n<heading>Standard Generalized Markup
Language</heading>
n<paragraph> ...
</paragraph>
n<section id=“content”>
n<heading>Content and
Presentation</heading>
n<paragraph> ...
</paragraph>
n... in section <reference
type=“section” id=“content”></reference> on page
<reference type=“page” id=“content”></reference> bla bla bla ...