Several authors have been interested in Ludwig Hamburger’s attempt to analyze business cycles with a nonlinear endogenous model in the early 1930s. Indeed, Hamburger was one of the first, if not the first, to suggest applying Van der Pol’s relaxation oscillations to business cycles. Ragnar...

This paper presents a classical-Keynesian one sector model of labor-constrained growth that explains secular stagnation as the result of structural change. Structural change is defined as an exogenous increase in the employment share of stagnant activities, which exhibit no or low labor...

We document that the nature of business cycles evolves over the process of development and structural change. In countries with large declining agricultural sectors, aggregate employment is uncorrelated with GDP. During booms, employment in agriculture declines while labor productivity increases...