The stellar population of the Rosat North Ecliptic Pole surveyG. Micela, L. Affer, F. Favata, J. P. Henry, I. Gioia, C. R. Mullis, J. Sanz Forcada and S. SciortinoA&A, 461 3 (2007) 977-982DOI: https://doi.org/10.1051/0004-6361:20066146