http://www.soc.mil/swcs/marquat.shtml
That is a great link. I used it a lot when I was in school. The link for other DoD libraries is especially good in my opinion since it has the NDU library link on it. From the NDU a person find student papers as far back 1985, I think. Some of them are really insightful.
There's also a link for papers from the War College going back to 1995.