RT Journal Article SR Electronic T1 Interferon β-1b reduced exacerbations in multiple sclerosis JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 53 OP 53 DO 10.1136/ebm.1996.1.53 VO 1 IS 2 YR 1996 UL http://ebm.bmj.com/content/1/2/53.abstract AB