Gaya APA

Nordhaus, W, D., Samuelson, P, A. (1989). Macroeconomics : a version of economics (13rd.ed.). New York: McGraw-Hill Book Co..

Gaya MLA

Nordhaus, William, D.., Samuelson, Paul, A.. "Macroeconomics : a version of economics". 13rd.ed. New York: McGraw-Hill Book Co., 1989. Text.