@book{60897,
	author = {Sprinz, Detlef F.},
	title = {Models, numbers, and cases  methods for studying international relations},
	publisher = {University of Michigan Press},
	year = {2004},
	address = {Ann Arbor (Míchigan, Estados Unidos)},
	url = {http://www.loc.gov/catdir/toc/ecip049/2003021557.html}
}