Boyce, R. R. (1982). Geographic perspectives on global problems: An introduction to geography. John Wiley and Sons.
Chicago-viite (17. p.)Boyce, Ronald Reed. Geographic Perspectives on Global Problems: An Introduction to Geography. New York: John Wiley and Sons, 1982.
MLA-viite (9. p.)Boyce, Ronald Reed. Geographic Perspectives on Global Problems: An Introduction to Geography. John Wiley and Sons, 1982.
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