use CGI qw/:html4 -no_xhtml/;

print $q->(-dtd=>'//W3C//DTD HTML 4.01//EN');


##</code><code>##

<"//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

##</code><code>##

print $q->(-dtd=>"'//W3C//DTD HTML 4.01//EN' 'http://www.w3.org/TR/html4/strict.dtd'");