@book{50999,
	author = {Boolos, George and Burgess, John P.},
	title = {Computability and logic /},
	publisher = {Cambridge University Press,},
	year = {2007},
	address = {Cambridge ;},
	edition = {5th ed.},
	url = {http://www.loc.gov/catdir/toc/ecip0715/2007014225.html}
}