1. Department of Neurosurgery, Desert Regional Medical Center, Palm Springs, CA,
2. Kentucky College of Osteopathic Medicine, University of Pikeville, Pikeville, KY,
3. College of Osteopathic Medicine, Western University of Health Sciences, Pomona, CA, United States,
4. School of Medicine, Universidad Anáhuac Querétaro, Cto. Universidades, Santiago, de Querétaro, Mexico,
5. William Beaumont School of Medicine, Oakland University, Rochester, Michigan,
6. Grossman School of Medicine, New York University, New York,
7. Department of Neurosurgery, University of Colorado, Aurora, Colorado, United States.