“…•'•For a general reference to benefit-cost analysis, see E. J. Mishan, Cost-Benefit Analysis , New York: Praeger, 1982. For a further description of life-cycle costing, see Rosalie Ruegg and Harold Marshall, "Economics Standards, NBSIR 82-2558, July 1982 costs from discounted benefits, the net benefits (or net losses) measured in either present value or annual value dollars can be determined. By dividing discounted benefits by discounted costs, a benefit-cost ratio can be calculated.…”