1. Department of Neurosurgery, Medical School, Midwestern University, Glendale, United States,
2. Department of Neurosurgery, University of Baghdad, College of Medicine, Medical City, Baghdad, Iraq,
3. University of Pittsburgh Medical Center (UPMC) Stroke Institute, Department of Neurology, University of Pittsburgh Medical Center, Pennsylvania, United States
4. Department of Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.