The needle in the haystack: where to look for more isolated cooling neutron starsB. Posselt, S. B. Popov, F. Haberl, J. Trümper, R. Turolla and R. NeuhäuserA&A, 482 2 (2008) 617-629DOI: https://doi.org/10.1051/0004-6361:20078430
