If production exhausts some resources and these are necessary in future production even though some substitution of producible resources is pos sible, how should the available stocks of exhaustible resources be allocated to present and future production? The objective considered is to maximize the present value of the utility of current and future consumption. When production functions are Cobb-Douglas and the utility functions are logarithmic, the optimum decision rule has the simple form: use up the fraction l-e of the remaining amount of every exhaustible resource in every period. Here fl...