A Forster, J Young, J Green, C Patterson, P Wanklyn, J Smith, J Murray, H Wild, S Bogle and K. Lowson
Age and Ageing 38 ( 5 ): 576 - 583 , 2009
A Forster, R Lambley and J. B. Young
Age and Ageing 39 ( 2 ): 169 - 175 , 2010