The compton-thick Seyfert 2 nucleus of NGC 3281: torus constraints from the 9.7 'mü'm silicate absorption - Sales, Dinalva A; Pastoriza, M. G; Riffel, R; Winge, C; Rodríguez-Ardila, A; Carciofi, Alex Cavaliéri (The Astrophysical Journal, 2011)