Where can I find upgrade cert test materials?

I hold a dual CLPP R5 certification and I'm looking forward to getting the upgrade certification tests as soon as possible. In order to get this status on the Lotus Certification Program, I took some courses. The course fees included some material (books) and references to IBM Red Books so that I could prepare to take the tests and achieve the Dual CLPP Certification. I've been working with Lotus Notes & Domino for six years (as a developer & administrator). At this time I wouldn't like to take any course to try the Certification Upgrade test. I'd rather to study all by myself since I feel confident that I can reach the grades required. The question is: where could I find some material to study for the tests. I'd prefer free stuff (not only IBM Red Books). Any information on this issue would be appreciated.