Palen, J. J. (1997). The urban world (5th ed.). McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Palen, J. John. The Urban World. 5th ed. New York: McGraw-Hill, 1997.
Lua MLA (9ú heag.)Palen, J. John. The Urban World. 5th ed. McGraw-Hill, 1997.
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