They like to reference Jude sometimes, which references the Book of Enoch.
Edit: It occurs to me that they don't often reference that passage though. So here it is, Jude 1:14-15:
14Enoch, the seventh from Adam, prophesied about them: “See, the Lord is coming with thousands upon thousands of his holy ones 15to judge everyone, and to convict all of them of all the ungodly acts they have committed in their ungodliness, and of all the defiant words ungodly sinners have spoken against him.”
Edit 2: To compare, here is 1 Enoch 2:1.
1Behold, he comes with ten thousands of his saints, to execute judgment upon them, and destroy the wicked, and reprove all the carnal for everything which the sinful and ungodly have done, and committed against him.
It strikes me now that they equate Jesus with Michael and call him the only archangel, completely ignoring the other 6 mentioned in the Book of Enoch. It's not as if they aren't aware of the contents of Enoch, so it's clear that they are being selective.