Predehl, Peter High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck Society;
Braig, C., & Predehl, P. (2012). Toward the diffraction limit with transmissive X-ray lenses in astronomy. Applied Optics, 51(20), 4638-4659. doi:10.1364/AO.51.004638.