Kraft, Heinrich. Die Offenbarung des Johannes. (HNT, 16a). Tübingen: Mohr, 1974.
Kraft is one of the strongest proponents for the influence of the OT. According to Kraft OT is the only source John uses: “Die alttestamentliche Prophetie ist die einzige Quelle, auf die er sich bei seinen Weisungen stützt” (p. 16). Furthermore, Kraft thinks that John felt himself to be the follower and ultimate interpreter of the OT prophecy to such a degree that John invented nothing of his own (p. 16). This commentary is a must.