Disorders of the Nervous System Caused by Drugs, Toxins, and Chemical Agents, Opiates and Synthetic Analgesic Drugs
Adams & Victors Principles of Neurology Chp 43, pg 1201, Ropper, A.H.,et al, 2014
Palliative Care in Neurology
Neurol 46:870-872, 5981996., Bernat,J.L.,et al, 1996