Evidence for precession of the isolated neutron star RX J0720.4-3125 F. Haberl, R. Turolla, C. P. De Vries, S. Zane, J. Vink, M. Méndez and F. Verbunt A&A, 451 2 (2006) L17-L21 Published online: 02 May 2006 DOI: 10.1051/0004-6361:20065093