Happiness Quantified: A Satisfaction Calculus Approach. : Oxford University Press, 2007-12-27. Oxford Scholarship Online. 2008-05-01. Date Accessed 18 May. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199226146.001.0001/acprof-9780199226146>.
(2007-12-27). Happiness Quantified: A Satisfaction Calculus Approach. : Oxford University Press. Retrieved 18 May. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199226146.001.0001/acprof-9780199226146.
Happiness Quantified: A Satisfaction Calculus Approach. : Oxford University Press, 2007-12-27. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199226146.001.0001/acprof-9780199226146.
van Praag BMS, Ferrer-i-Carbonell A. Happiness Quantified: A Satisfaction Calculus Approach. Oxford University Press; 2007. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199226146.001.0001/acprof-9780199226146. Accessed May 18, 2013.