i won't recommend using too many outside sources - no more than a couple of sentences from each - yes you're supposed to but its very difficult to pick up marks from places other than the given info... (especially true for diagrams) and with the strict word limit you can't waste words!
I'd put down references but wouldn't use them too much, stick to cutting down the relevant info in the booklet to 1000 words - that's what i did and (not bragging honestly!) got full marks...