<!-- here we declare all shared entities -->

<!ENTITY copyright "Copyright © 1998-2002 Acme Inc.">
<!-- (Unicode character 00A9 is the copyright symbol) -->
<!ENTITY legalese "(really long legal disclaimer)">
<!-- ...other shared DTD declarations go here... -->

<!DOCTYPE book PUBLIC "..." "..."
[
<!-- declare the common.dtd entity: -->
<!ENTITY common SYSTEM "w:\share\common.dtd">
<!-- include the common.dtd entity: -->
%common;
]>

<book>
<frontmatter>
<!-- include the standard copyright and disclaimer: -->
<p>&copyright;</p>
<p>&legalese;</p>
...