Use keywords describing your diagnostic group to get started searching. Your textbook is an excellent source of search terms.
It's a good idea to keep track of search terms you're using and what you're finding. This will help you figure out what's working, and what's not, as you gather materials for research!
Coming up with Keywords
Taking a few minutes to think about and identify some keywords before starting your search will help you search more efficiently, which will save you time (and probably a little frustration).