@article{Brekke2003,
	title = {An economic model of moral motivation},
	author = {Kjell Arne Brekke and Snorre Kverndokk and Karine Nyborg},
	journal = {Journal of Public Economics},
	month = {Sep},
	number = {9-10},
	pages = {1967--1983},
	url = {http://www.sciencedirect.com/science/article/B6V76-44X05KM-1/1/de1bc8e15e121483e383b525ef752c3e},
	volume = {87},
	year = {2003},
	biburl = {http://www.bibsonomy.org/bibtex/2da5280afcf3452ce4930f1b4603d2cd6/smicha},
	keywords = {Voluntary contributions }
}