Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis. - Lindenbaum,J.; Healton,E.B.; Savage,D.G.; Brust,J.C.; Garrett,T.J.; Podell,E.R.; Marcell,P.D.; Allen,R.H. (N Engl J Med, 1988)