Giesen, Heinz. Die Offenbarung des Johannes. Regensburger NT. Regensburg: Verlag Friedrich Pustet, 1997.
Giesen, a Catholic Professor of the NT, has written an extremely well-researched commentary. The 562 pages is replete with research surveys, excursuses, and detailed discussions. Many of the discussions has been published as major articles at least since 1981/1982. Martyrdom is a major theme in this commentary.