ÜLTAY, N.; ÜLTAY, E. Cross-age Study on The Development of “Chemistry” Concept Through Different Grades: 7th, 9th And 11th Grades. International Journal of Physics and Chemistry Education, [S. l.], v. 1, n. 2, p. 52–69, 2009. Disponível em: https://www.ijpce.org/index.php/IJPCE/article/view/4. Acesso em: 25 apr. 2024.