Gaya APA

SAMUELSON, P, A., NORDHAUS, W, D. (2005). ECONOMICS (EIGHTEENTH EDITION). AMERIKA SERIKAT: MC GRAW HILL.

Gaya MLA

SAMUELSON, PAUL, A.., NORDHAUS, WILLIAM, D.. "ECONOMICS". EIGHTEENTH EDITION AMERIKA SERIKAT: MC GRAW HILL, 2005. Text.