@inbook{30,
  author = {Alan Krueger and Daniel Kahneman and David Schkade and Norbert Schwarz and Arthur Stone},
  title = {National time accounting: The currency of life},
  abstract = {  },
  year = {2009},
  journal = {Measuring the subjective well-being of nations: National accounts of time use and well-being},
  pages = {9{\textendash}86},
  publisher = {University of Chicago Press},
  language = {eng},
}