The role of HLA-DRB1 alleles on susceptibility and outcome of a Portuguese Multiple Sclerosis population - Silva, A.M.; Pereira, C.; Bettencourt, A.; Carvalho, C.; Couto, A.R.; Leite, M.I.; Marta, M.; Freijo, M.; Costa, P.P.; Mendonça, D.; Monteiro, L.; Armas, J.B.; et al. (Journal of the Neurological Sciences, 2007)