The article discusses various aspects of Sraffa's economic theory, focusing on technical change, variable returns, and normal prices. Researchers analyze the consistency between long-period methods and given quantities, as well as the gravitation of market prices towards natural prices. They also explore output and distribution in the long run from a classical-Keynesian perspective. The relevance of the classical approach for economic and social policy issues is highlighted, along with historical issues in Sraffa's writings. Key findings include the analysis of investment determinants, the principle of effective demand, and the impact of monetary influences on distribution.