A search for planetary-mass objects and brown dwarfs in the Upper Scorpius associationM. T. Costado, V. J. S. Béjar, J. A. Caballero, R. Rebolo, J. Acosta-Pulido and A. ManchadoA&A, 443 3 (2005) 1021-1024DOI: https://doi.org/10.1051/0004-6361:20053048