DE BLIJ, H. J., & MULLER, P. O. (1988). Geography: Regions and concepts.-- ed.5. John Wiley and Sons.

DE BLIJ, Harm J., and Peter O. MULLER. Geography: Regions and Concepts.-- Ed.5. New York: John Wiley and Sons, 1988.

DE BLIJ, Harm J., and Peter O. MULLER. Geography: Regions and Concepts.-- Ed.5. John Wiley and Sons, 1988.