Lazarov Б. On students’ achievements assessment in Chernorizec Hrabar Tournament and TIMSS. Mathematics and Education in Mathematics, [S. l.], v. 49, p. 229–233, 2020. Disponível em: https://smb.math.bas.bg/mem/index.php/memjournal/article/view/120. Acesso em: 7 oct. 2026.