Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) CLARKE MJ,Spinal extradural arteriovenous malformations with parenchymal drainage : venous drainage variability and implications in clinical manifestations,Neurosurg Focus,,,2009,26,,E5,https://cir.nii.ac.jp/crid/1573387451139535616,