No disks around low-mass stars and brown dwarfs in the young σ Orionis cluster? J. M. Oliveira, R. D. Jeffries, M. J. Kenyon, S. A. Thompson and T. Naylor A&A, 382 3 (2002) L22-L25 Published online: 15 February 2002 DOI: 10.1051/0004-6361:20011778