Gaya APA

Swanson, C, P., Ricardo, D. (NULL). The Principles of Political Economy and Taxation . London:: London: J.M. Dent & Sons; 1949.

Gaya MLA

Swanson, Carl, P.., Ricardo, David. "The Principles of Political Economy and Taxation". London:: London: J.M. Dent & Sons; 1949, NULL. Text.