PERWITASARI, Dewi; SURYA, Edy. The Development of Learning Material Using Problem Based Learning to Improve Mathematical Communication Ability of Secondary School Students. International Journal of Sciences: Basic and Applied Research (IJSBAR), Jordan, v. 33, n. 3, p. 200–207, 2017. Disponível em: https://www.gssrr.org/JournalOfBasicAndApplied/article/view/7382. Acesso em: 18 sep. 2025.