Wetzel F T, Wilson S C, Manale B L, Frauenhoffer E E
Division of Orthopaedic Surgery, Milton S. Hershey Medical Center of The Pennsylvania State University, Hershey.
Spine (Phila Pa 1976). 1992 Oct;17(10):1259-64. doi: 10.1097/00007632-199210000-00025.