The value of adding impedance plethysmography to 125I- fibrinogen leg scanning for the detection of deep vein thrombosis in high risk surgical patients: a comparative study between patients undergoing general surgery and hip surgery - Hull, R; Hirsh, J; Sackett, D L; Powers, P; Turpie, A GG; Walker, I; McBride, J (Thromb Res, 1979)