"In a proto-Austrian manner, Donisthorpe also distinguished between directly useful and indirectly useful goods, and showed how the latter had varying degrees of remoteness from the pleasure-giving stage of goods; in short, Donisthorpe engaged in a sophisticated analysis of the time-structure of production. He also had a pioneering analysis of the influence of substitutes and complements ('co-elements') upon values. While Donisthorpe's discussion of demand curves (i.e. schedules), supply, and price was interesting but hopelessly confused (e.g. he denied that an increased desire of consumers for a product would raise their demand for the product), he did present a remarkably clear foreshadowing of Philip Wicksteed's insight of four decades later that witholding the stock of a product by suppliers really amounts to the suppliers' 'reservation demand' for that product."