Thoman, R. S. (1964). Focus on geographic activity: A collection of original studies/ by. McGraw-Hill.
Chicago-čujuhus (17. p.)Thoman, Richard S. Focus on Geographic Activity: A Collection of Original Studies/ by. New York: McGraw-Hill, 1964.
MLA-čujuhus (9. p.)Thoman, Richard S. Focus on Geographic Activity: A Collection of Original Studies/ by. McGraw-Hill, 1964.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.