Diseases of the Nervous System Caused by Nutritional Deficiency, Vitamin B12 (Cobalamin) Deficiency (Subacute Combined Degeneration)
Adams & Victors Principles of Neurology Chp 41, pg 1172, Ropper, A.H.,et al, 2014
Parkinson's Disease
JNNP 57:672-681, Marsden,C.D., 1994