@article {litwin2006association,
	title = {The association between activity and wellbeing in later life: what really matters?},
	journal = {Ageing \& Society},
	volume = {26},
	number = {2},
	year = {2006},
	pages = {225{\textendash}242},
	publisher = {Cambridge University Press},
	author = {Litwin, Howard and Shiovitz-Ezra, Sharon}
}
