Where does DTD declare XSL?

Can someone please tell me where the docbook dtd is supposed to declare 
the stylesheet? I get the following error:

"The element 'xsl:stylesheet' is used but not declared in the DTD/Schema."

Here are the declarations:

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2CR1//EN"
"g:/docbookx/docbookx.dtd">
<?xml-stylesheet type="text/xsl"
    href="g:/docbook-xsl-1.58.1/html/docbook.xsl"?>

I performed a search for the xsl element in the docbook directory but it 
returned nothing.

Thanks, Jeff Biss