RT Journal Article SR Electronic T1 Multiple sclerosis in the Orkney and Shetland Islands. VI: The effects of migration and social structure. JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 271 OP 276 DO 10.1136/jech.34.4.271 VO 34 IS 4 A1 R Taylor A1 R Illsley A1 D C Poskanzer YR 1980 UL http://jech.bmj.com/content/34/4/271.abstract AB