A mid-infrared study of very low mass stars and brown dwarfs in Upper Scorpius H. Bouy, N. Huélamo, E. L. Martín, D. Barrado y Navascués, M. Sterzik and E. Pantin A&A, 463 2 (2007) 641-646 Published online: 27 November 2006 DOI: 10.1051/0004-6361:20066096