This paper investigates the effect of human capital accumulation on the direction of technical Change in a framework with natural resources and environmental externalities. The model simulates that an increasing knowledge stock of worker tends to direct technical change in favour of intangible...

This paper combines three prototype endogenous growth models, the models with human capital accumulation introduced by Uzawa [1965] and Lucas [1988], variety expansion by Romer [1990], and quality improvements by Aghion and Howitt [1992], in order to investigate how these three engines of growth...