1. Auricular paroxysmal tachycardia with alternation of cycle length;Barker, P.S.; Johnston, F.D.; Wilson, F.N.;American Heart journal,1943
2. Alternation of A-V conduction time;Langendorf, R.;American Heart Journal,1958
3. Two or more intra AV nodal pathways in association with either a James or Kent extranodal bypass in 3 patients with paroxysmal supraventricular tachycardia;Spurrell, R.A.J.; Krikler, D.; Sowton, E.;British Heart Journal,1973