The ultra luminous X-ray source NuSTAR J095551+6940.8: A magnetar in a high mass X-ray binary - K. Y. Ekşi; İ. C. Andaç and S. Çıkıntoğlu and A. A. Gençali and C. Güngör and F. Öztekin (Monthly Notices of the Royal Astronomical Society, 2015)