A Long Observation of NGC 5548 by BeppoSAX: The High-Energy Cutoff, Intrinsic Spectral Variability, and a Truly Warm Absorber

Nicastro, F.; Piro, L.; De Rosa, A.; Feroci, M.; Grandi, P.; Fiore, F.; Elvis, M.; Haardt, Francesco; Kaastra, J.; Malizia, A.; Maraschi, L.; Matt, G.; Perola, G. C.; Petrucci, P. ).