Low metallicity and ultra-luminous X-ray sources in the Cartwheel galaxy

Mapelli Michela, Colpi Monica, Zampieri Luca, Low metallicity and ultra-luminous X-ray sources in the Cartwheel galaxy, 2009, MNRAS, 395L, 71, http://ui.adsabs.harvard.edu/abs/2009MNRAS.395L..71M