@book{689,
	author = {FRANK, H.R. and BERNANKE, S. B. , OSBERG,, L. , CROSS, L. M.  &  MAcLEAN, K. B.},
	title = {Principles of Macro Economics.},
	publisher = {McGraw-Hill,},
	year = {2009.},
	address = {New York,},
	edition = {3rd Ed.}
}