Example (1)

<!DOCTYPE book SYSTEM
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<?xml-stylesheet href="http://www.example.org/styles/style.xsl" type="text/css"?>
<book>…</book>

Becomes

<!DOCTYPE book SYSTEM
  "/path/to/docbookx.dtd">
<?xml-stylesheet href="/local/copy/of/style.xsl" type="text/css"?>
<book>…</book>