Scheffer, Nilce Fátima, and Arthur Belford Powell. “Fractions in Brazilian Textbooks of The National Program of Didactic Books (PNLD)”. Revemop 1, no. 3 (September 1, 2019): 476–503. Accessed November 12, 2026. https://periodicos.ufop.br/revemop/article/view/1977.