Kaldor proposed a ordinary differential system to model business cycle, in which the gross investment depends on the level of output and capital stock. Thereafter, this model was often discussed, see and references there in. The Kalecki business model was a few years earlier than the Kaldor one.
Kalecki assumed that the saved part of profit is invested and the capital growth is due to past investment decisions. There is a gestation period or a time lag, after which capital equipment is available for production. In 1999, Krawiec and Szydlowski have formulated the Kaldor-Kalecki business cycle model based on the multiplier dynamics which is the core of both the Kaldor (after Keynes) and Kalecki approach. Read More>>>>>>>>>>