The only sure way I've found (so far, anyway) to include documents or articles reported elsewhere without getting flagged is to:
1. Break the desired material into fairly small chunks (no larger than 1 or 2 paragraphs at most.
2. Surround these insertions with original text of your own that is significantly longer in length than the material you're studying.
Others may have better ideas, but so far that's worked for me.