Lindh, C., Thörnwall, M., Hansen, A.-C., Post, C., Gordh, T., Ordeberg, G., & Nyberg, F. (1996). Neuropeptide-converting enzymes in cerebrospinal fluid:Activities increased in pain from herniated lumbar disc, but not from coxarthrosis. Acta Orthopaedica, 67(2), 189–192. https://doi.org/10.3109/17453679608994670