Olson, S. (2004). Count down: Six kids vie for glory at the world's toughest math competition. Boston: Houghton Mifflin Company.
Čikaški stil citiranjaOlson, Steve. Count Down: Six Kids Vie for Glory At the World's Toughest Math Competition. Boston: Houghton Mifflin Company, 2004.
MLA način citiranjaOlson, Steve. Count Down: Six Kids Vie for Glory At the World's Toughest Math Competition. Boston: Houghton Mifflin Company, 2004.
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