T. A Ashfield, H. E Syddall, H. J Martin, E. M Dennison, C Cooper and A. A. Sayer
Age and Ageing 39 ( 2 ): 185 - 191 , 2010
H Syddall, H. C Roberts, C Cooper, H Bergman and A. A. Sayer
Age and Ageing 39 ( 2 ): 197 - 203 , 2010