Gaya APA

Ruffin, R, J, 1., Gregory, P, R. (1983). Principles of macroeconomics . Glenview, Ill: Scott, Foresman and Co..

Gaya MLA

Ruffin, Roy, J., 1938., Gregory, Paul, R. "Principles of macroeconomics". Glenview, Ill: Scott, Foresman and Co., 1983. Text.