The needle in the haystack: where to look for more isolated cooling neutron stars B. Posselt, S. B. Popov, F. Haberl, J. Trümper, R. Turolla and R. Neuhäuser A&A, 482 2 (2008) 617-629 Published online: 20 February 2008 DOI: 10.1051/0004-6361:20078430