Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Barrett YC,Clinical laboratory measurement of direct factor Xa inhibitors: anti‐Xa assay is preferable to prothrombin time assay,Thromb Haemost,,,2010,104,,263,https://cir.nii.ac.jp/crid/1370580230634586769,