Unveiling the nature of INTEGRAL objects through optical spectroscopy - VII. Identification of 20 Galactic and extragalactic hard X-ray sources
N. Masetti, P. Parisi, E. Palazzi, E. Jiménez-Bailón, L. Morelli, V. Chavushyan, E. Mason, V. A. McBride, L. Bassani, A. Bazzano, A. J. Bird, A. J. Dean, G. Galaz, N. Gehrels, R. Landi, A. Malizia, D. Minniti, F. Schiavone, J. B. Stephen and P. Ubertini
A&A, 495 1 (2009) 121-135
DOI: https://doi.org/10.1051/0004-6361:200811322
