Boyce, R. R. (1982). Geographic perspectives on global problems: An introduction to geography. John Wiley and Sons.
Chicago-čujuhus (17. p.)Boyce, Ronald Reed. Geographic Perspectives on Global Problems: An Introduction to Geography. New York: John Wiley and Sons, 1982.
MLA-čujuhus (9. p.)Boyce, Ronald Reed. Geographic Perspectives on Global Problems: An Introduction to Geography. John Wiley and Sons, 1982.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.