Dorfler A, Schulte K, Neuwirth A, Gross W, Schnabel P, Allenberg JR. Grading of internal carotid artery stenosis: Validation of Doppler/duplex ultrasound criteria and angiography against endarterectomy specimen. - Eckstein,H.H.; Winter,R.; Eichbaum,M.; Klemm,K.; Schumacher,H. (Eur J Vasc Endovasc Surg, 2001)