@article{Llewellyn2008,
author = {David Llewellyn and Iain Lang and Kenneth Langa and Felicia Huppert},
title = {Cognitive function and psychological well-being: a population-based study},
journal = {Age and Ageing},
year = {2008},
month = {Nov},
volume = {37},
number = {6},
pages = {685-689},
url = {http://ageing.oxfordjournals.org/cgi/content/abstract/37/6/685},
}