Voges, Wolfgang High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck Society;
Collinge, M. J., Strauss, M. A., Hall, P. B., Ivezić, Z., Munn, J. A., Schlegel, D. J., et al. (2005). Optically identified BL lacertae objects from the sloan digital sky survey. The Astronomical Journal, 129(6), 2542-2561. doi:10.1086/430216.