Zimmermann, Hans Ulrich High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck Society;
Brunner, H., Friedrich, P., Zimmermann, H. U., & Staubert, R. (1992). Spectra of radio-loud quasars observed in the ROSAT/XRT all sky survey. In W. Brinkmann, & J. Trümper (Eds.), X-Ray Emission from Active Galactic Nuclei and the Cosmic X-Ray Background: Proceedings of a Conference held at the Max-Planck-Institut für extraterrestrische Physik (pp. 198-201). Garching, Germany: Max-Planck-Institut für extraterrestrische Physik.
