Gaya APA

, ., Lenchner, G. (2006). Math olympiad: contest problems for elementary and middle schools . New York: New York: Math Olympiads for Elementary and Middle Schools, 2006.

Gaya MLA

, ., Lenchner, George. "Math olympiad: contest problems for elementary and middle schools". New York: New York: Math Olympiads for Elementary and Middle Schools, 2006, 2006. .