Sraffa, Marshall and the problem of returns

The paper deals with some links between Sraffa's 1920s work on Marshallian supply functions and his 1960 book. It argues that content of Sraffa's 1920s articles can justify that lack of reference in Production of Commodities to the analysis of the firm. Besides, it can claify Sraffa's position on the determinants of variable returns and some origins of the method based on the assumption of ‘given quantities’. which characterizes has later book. It also argues that some important aspects of the development of Production of Commodities find their origin in the Marshallian tradition as well as in the ‘classical’ one.