Gaya APA

Leftwich, A, M, S, ;, C, A, R, ;, R, H. (1988). Economics of social issues (ed. 8). USA: BPI.

Gaya MLA

Leftwich, Ansel, M., Sharp, ;, Charles, A., Register, ;, Richard, H.. "Economics of social issues". ed. 8 USA: BPI, 1988. Text.