Further identification of ROSAT all-sky survey sources in Orion A. Frasca, J. M. Alcalá, E. Covino, S. Catalano, E. Marilli and R. Paladino A&A, 405 1 (2003) 149-163 Published online: 16 June 2003 DOI: 10.1051/0004-6361:20030644