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Other sources

Keynes does not cite a specific source for the phrase, and, as it does not appear to be found in the pre-Keynesian literature, some consider its ultimate origin a "mystery". The phrase "supply creates its own demand" appears earlier, in quotes, in a 1934 letter of Keynes, and has been suggested that the phrase was an oral tradition at Cambridge, in the circle of Joan Robinson, and that it may have derived from the following 1844 formulation by John Stuart Mill: