dtd:how to limit the depth of an element

["Hubert Holtz" <Turnhose_alt@gmx.net>]

Hy,

I want to use a sect element in my xml, which can be used for 3 levels of depth.
That's how it looks at the moment, but i know this doesn't limit the depth.

<!ELEMENT sect (titel,(sect|link|email|adresse|liste|para|form|bericht
				|projekt|faq|kurs|dozenten)*)>
..

With this dtd it's possible to use sect inside a sect as often as I want, which is fine.
But it doesn't limit the depth, how to do that?


Thanks
Homer30