Andersen, K. S. and Sneppen, O. (1968) “Comparative Study of Myelography Filling Defects in Root Sheaths and Operative Findings in Cases of Suspected Lumbar Intervertebral Disc Herniation”, Acta Orthopaedica, 39(1-3), pp. 312–320. doi: 10.3109/17453676808989464.