Organizational Index Mapping to Identify Focal Sources During Persistent Atrial Fibrillation - Jarman, JWE; Wong, T; Kojodjojo, P; Spohr, H; Davies, JER; Roughton, M; Francis, DP; Kanagaratnam, P; O'Neill, MD; Markides, V; Davies, DW; Peters, NS (JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, 2014)