Are Combination Gas and Electric Utilities Multiproduct Natural Monopolies?
通过估计多产品混合超越对数成本函数，检验联合提供燃气和电力的公司是否存在范围经济和产品规模经济，发现平均产出水平下不存在此类经济性。
Gas and electric services are provided in some locations by a single firm, in others by two firms. The loss of competition inherent in single-firm provision can be justified by the presence of both economies of scope and product-specific economies of scale for each output in multiproduct production. The estimation of a multiproduct, hybrid, translog cost function shows no evidence of such economies at the mean combination utility output vector. Copyright 1987 by MIT Press.