High-z nebulae: Ionization by stars or by an obscured QSO? L. Binette, B. Groves, M. Villar-Martín, R. A. E. Fosbury and D. J. Axon A&A, 405 3 (2003) 975-980 Published online: 30 June 2003 DOI: 10.1051/0004-6361:20030718