RT Journal Article SR Electronic T1 Vitamin D in MS JF Neurology JO Neurology FD Lippincott Williams & Wilkins DO 10.1212/WNL.0b013e31825fe131 A1 Ascherio, Alberto A1 Marrie, Ruth Ann YR 2012 UL http://n.neurology.org/content/early/2012/06/13/WNL.0b013e31825fe131.abstract AB