I don't have anything more than Newton's third law for you and that its effects also hold in general relativity. The "far away parts of the universe are disconn

I don't have anything more than Newton's third law for you and that its effects also hold in general relativity. The "far away parts of the universe are disconnected" is from my astrophysics courses back in university and the number of lectures to the cosmic microwave background, mostly coming from people discussing the Planck mission. But.. no, I don't have a convenient citation for you. And at least for the "angular momentum is conserved thing", I'd be surprised if you'd find a google scholar paper, this is early GR