Orlando, E. High Energy Astrophysics, MPI for Extraterrestrial Physics, Max Planck Society;
Abdo, A. A., Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., et al. (2011). Fermi Large Area Telescope observations of Markarian 421: the missing piece of its spectral energy distribution. The Astrophysical Journal, 736(2): 131, pp. 1-22. doi:10.1088/0004-637X/736/2/131.