Bilateral sequential cochlear implantation in the congenitally deaf child: evidence to support the concept of a “critical age” after which the second ear is less likely to provide an adequate level of speech perception on its own - Graham, J; Vickers, D; Eyles, J; Brinton, J; Al Malky, G; Aleksy, S; Martin, J; Henderson, L; Mawman, D; Robinson, P; Midgley, E; Hanvey, K; Twomey, T; Johnson, S; Vanat, Z; Broxholme, C; McAnallen, C; Allen, A; Bray, M (Cochlear implants international, 2009)