CLAESSEN, F.; DAEMEN, W. Investeren in lesmateriaal. Levende Talen Magazine, Utrecht, Nederland, v. 87, n. 3, p. 11–15, 2000. Disponível em: https://lt-tijdschriften.nl/ojs/index.php/ltm/article/view/790. Acesso em: 25 apr. 2024.