The explanatory value of glutamatergic SNPs on combined MRI phenotypes in multiple sclerosis - Strijbis,EMM; Inkster,B; Vounou,M; Kappos,L; Radu,E-W; Matthews,PM; Uitdehaag,B; Barkhof,F; Geurts,JJG (MULTIPLE SCLEROSIS JOURNAL, 2011)