APA (7th ed.) Citation

Ricardo, D., & Hartwell, R. M. (1971). On the principles of political economy, and taxation. Penguin.

Chicago Style (17th ed.) Citation

Ricardo, David, and R. M. Hartwell. On the Principles of Political Economy, and Taxation. Harmondsworth: Penguin, 1971.

MLA (9th ed.) Citation

Ricardo, David, and R. M. Hartwell. On the Principles of Political Economy, and Taxation. Penguin, 1971.