Demonstration of dual atrioventricular nodal pathways utilizing a ventricular extrastimulus in patients with atrioventricular nodal re-entrant paroxysmal supraventricular tachycardia. - Wu,D.; Denes,P.; Wyndham,C.; Leon,F.; Dhingra,R.C.; Rosen,K.M. (Circulation, 1975)