Since the introduction of "A Theory of Production," by C. Cobb and P. H. Douglas in 1928, the investigation of substitution possibilities among different inputs into production has been the subject of numerous studies. There has been a revitalized interest in the study of production frameworks, with a special focus on the examination of the substitution characteristics among various types of energy inputs and between energy and non-energy production inputs. The most popular of the n-factor functional forms applied to the study of production structures bearing several inputs is the generalized form of the Cobb-Douglas production function, which is commonly referred to as the translog production frontier. Many applications of translog modeling of production structures have placed somewhat limiting, restrictive assumptions on the homotheticity of the aggregate production function and on the neutrality of technological change in the structure. The restrictive assumptions have, in some instances, been placed on the structures due to the lack of data or for greater simplicity in estimation. For example, Berndt and Wood [1975] used a translog model to estimate a fourinput aggregate production structure, assuming constant returns to scale and Hicksneutral technological change. Fuss [1977] and Pindyck [1979] both used translog frontiers to model four-input and three-input aggregate production structures, respectively, with the energy input disaggregated into several components. In each case, a nonhomothetic aggregate structure was modeled, while technological change was assumed to be Hicks-neutral. Denny, Fuss, and Waverman [1979] utilized the same