Trigonometric parallaxes of high velocity halo white dwarf candidates C. Ducourant, R. Teixeira, N. C. Hambly, B. R. Oppenheimer, M. R. S. Hawkins, M. Rapaport, J. Modolo and J. F. Lecampion A&A, 470 1 (2007) 387-394 Published online: 11 April 2007 DOI: 10.1051/0004-6361:20066876