PRISMS-4: Long-term efficacy of interferon-beta-1a in relapsing MS حسب Francis, G, Hughes, R, King, J, Mitchell, P, Joubert, J, McLeod, J, Parker, G, Pollard, J, Sindic, C, Duprez, T, Medaer, R, Broeckx, J, Vanroose, E, Carton, H, Wilms, G, Rice, G, Ebers, G, Lee, D, Freedman, M, Nelson, R, Rabinovitch, H, Christie, S, Avruch, L, Oger, J, Paty, D