Tài liệu tham khảo WikiPedia: Lê_Bá_Khánh_Trình http://www.imo-official.org/country_individual_r.a... http://www.imo-official.org/participant_r.aspx?id=... http://mi.mathnet.ru/vmumm3085 http://www.thanhnien.com.vn/pages/20130727/viet-na... http://www.thanhnien.com.vn/pages/20130915/su-%E2%... http://www.math.hcmuns.edu.vn/index.php?option=com... http://vietnamnet.vn/giaoduc/2005/06/463359/ http://vietnamnet.vn/giaoduc/vande/2005/03/397537/ https://vnexpress.net/cau-be-vang-toan-hoc-viet-na... https://iopscience.iop.org/article/10.1070/SM1992v...
