The best place to find resources that apply to Lotus exams is on the preparation page for each exam. Some of these are free, some are for sale. To find these, click here and select either the certification you want to pursue or go directly to an exam.
Also, check your library. Many carry technical preparation books. And don't forget a study group see if you can get together with some colleagues and study.
Do you have comments on this Ask the Expert Q&A? Let us know.