OXMAN, V.; STUPEL, M. Proof Without Words: Trisection of a Parallelogram’s Diagonal (p. 58). Ohio Journal of School Mathematics, [S. l.], v. 84, n. 1, 2020. Disponível em: https://www.osu.tests.sfulib4.publicknowledgeproject.org/index.php/OJSM/article/view/7602. Acesso em: 30 apr. 2026.