International longitudinal registry of patients with atrial fibrillation and treated with rivaroxaban: RIVaroxaban Evaluation in Real life setting (RIVER) oleh Jan Beyer-Westendorf, A. John Camm, Keith A. A. Fox, Jean-Yves Le Heuzey, Sylvia Haas, Alexander G. G. Turpie, Saverio Virdone, Ajay K. Kakkar, for the RIVER Registry Investigators