Gaya APA
S.Barden, D., C.Starr's, P. (1978).
Economics:Principles in Action .
California:
Wadsworth Publishing Company,INC.
Gaya MLA
S.Barden, Drew., C.Starr's, Philip.
"Economics:Principles in Action".
California:
Wadsworth Publishing Company,INC,
1978.
Text.