@book{62456,
	author = {MacCormick, Neil},
	title = {Institutions of law  an essay in legal theory},
	publisher = {Oxford University Press},
	year = {2007},
	series = {Law, State, and Practical Reason},
	address = {Nueva York (Estados Unidos)},
	url = {http://www.loc.gov/catdir/toc/ecip072/2006033081.html}
}