@book{481668,
	author = {Lewis-Beck, Michael S. and Sage eBooks},
	title = {The SAGE encyclopedia of social science research methods},
	publisher = {SAGE,},
	year = {2003.},
	address = {Thousand Oaks, [Calif.] ;},
	url = {http://methods.sagepub.com/reference/the-sage-encyclopedia-of-social-science-research-methods}
}