Growth in Cities
利用1956-1987年美国170个城市的大产业数据，检验了不同增长理论，发现本地竞争和城市多样性（而非区域专业化）促进了产业就业增长，表明知识溢出可能发生在产业之间而非内部。
Recent theories of economic growth, including those of P. Romer (1986, 1990), M. Porter (1990), and J. Jacobs (1969, 1984), have stressed the role of technological spillovers in generating growth. Because such knowledge spillovers are particularly effective in cities, where communication between people is more extensive, data on the growth of industries in different cities allow the authors to test some of these theories. Using a new data set on the growth of large industries in 170 U.S. cities between 1956 and 1987, they find that local competition and urban variety, but not regional specialization, encourage employment growth in industries. The evidence suggests that important knowledge spillovers might occur between rather than within industries. Copyright 1992 by University of Chicago Press.