King, Anthony. 1990. Global Cities: Post-Imperialism and the Internationalisation of London. London and New York: Routledge.
Time, special issue on Megacities, 11 January 1993.
Sassen, Saskia. 1990. The Global City: New York, London, Tokyo. Prineceton: Princeton University Press
Wilson, Elizabeth. 1991. "World Cities." In The Sphinx in the City: Urban Life, the Control of Disorder, and Women. Berkeley, Los Angeles, and Oxford: University of California Press: 121-34.