Hijji FY, Massel DH, Mayo BC, Narain AS, Long WW, Modi KD, Burke RM, Canar J, Singh K. Spinal Surgeon Variation in Single-Level Cervical Fusion Procedures: A Cost and Hospital Resource Utilization Analysis. Spine (Phila Pa 1976). 2017 Jul 01; 42(13):1031-1038.