Astrometric monitoring of the binary brown dwarf DENIS-P J1228.2-1547W. Brandner, E. L. Martín, H. Bouy, R. Köhler, X. Delfosse, G. Basri and M. AndersenA&A, 428 1 (2004) 205-208DOI: https://doi.org/10.1051/0004-6361:20041912