stylized result of increasing one productive input while holding the others constant (versus increasing all inputs, generating economiesof scale). 李嘉图反对关税以及其他对于国际贸易的限制
1989), pp. 223–25. Marshall, Alfred. Appendix C: 'The scope and method of economics'. Principles of Economics 8th. London: MacMillan & Co. 1920 [First published