Lichti, G. G., Bottacini, E., Ajello, M., Charlot, S., Collmar, W., Falcone, A., Horan, D., Huber, S., Kienlin, A. v., Lähteenmäki, A., Lindfors, E., Morris, D., Nilsson, K., Petry, D., Rüger, M., Sillanpää, A., Spanier, F., & Tornikoski, M. (2008). INTEGRAL observations of the blazar Mrk 421 in outburst: results of a multi-wavelength campaign. Astronomy & Astrophysics, 486(3), 721-734. doi:10.1051/0004-6361:20079199.