Thoman, R. S., Conkling, E. C., & Yeates, M. (1968). The geography of economic activity. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Thoman, Richard S., Edgar C. Conkling, agus Maurice Yeates. The Geography of Economic Activity. New York: McGraw-Hill, 1968.
Lua MLA (8ú heag.)Thoman, Richard S., et al. The Geography of Economic Activity. McGraw-Hill, 1968.
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