Gaya APA
Byrns, R, T., Stone, G, W.
(1989).
Economics
(
Ed. 4)
.
Usa:
Scott, Foresman and Company.
Gaya MLA
Byrns, Ralph, T., Stone, Gerald, W.
"Economics".
Ed. 4
Usa:
Scott, Foresman and Company,
1989.
Text.