deny access for specific files

[ciber]

I have created a PHP application, which uses apache rewrite for the URLs, my problem is the rewritten urls are very similar to some of the files im using, is there a way to deny direct access to these files using htaccess?

 

for example x.php, y.php and z.html

[premiso]

http://www.garnetchaney.com/htaccess_tips_and_tricks.shtml

 

Search for "Protecting Single File"  on that page for examples.