Pietsch, W. High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck Society;
Kollatschny, W., Kotulla, R., Pietsch, W., Bischoff, K., & Zetzl, M. (2008). New active galactic nuclei detected in ROSAT all sky survey galaxies - II. The complete dataset. Astronomy & Astrophysics, 484(3), 897-915. doi:10.1051/0004-6361:20078552.