Berry, B. J. L., Horton, F. E., & Abiodun, J. O. (1970). Geographic perspectives on urban systems: With integrated readings. Prentice-Hall.
Lua i Stíl Chicago (17ú heag.)Berry, Brian Joe Lobley, Frank E. Horton, agus Josephine Olu Abiodun. Geographic Perspectives on Urban Systems: With Integrated Readings. Englewood Cliffs, N. J: Prentice-Hall, 1970.
Lua MLA (9ú heag.)Berry, Brian Joe Lobley, et al. Geographic Perspectives on Urban Systems: With Integrated Readings. Prentice-Hall, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.