| − | Neo-classical economics flourished between 1870 and World War I in Europe and the United States. It focused on principles of allocation theory and price, and also "[[marginalism]]". This approach relied heavily on calculus. Modern economics builds on this work. | + | Neo-classical economics flourished between 1870 and [[World War I]] in [[Europe]] and the [[United States]]. It focused on principles of allocation theory and price, and also "[[marginalism]]". This approach relied heavily on [[calculus]]. Modern economics builds on this work. |