Roberts , Douglas A., and Graham W. F. Orpwood. “Classroom Events and Curricular Intentions: A Case Study in Science Education”. Canadian Journal of Education Revue Canadienne De l’éducation, vol. 7, no. 2, Jan. 1982, pp. 1-15, https://cje.journals.publicknowledgeproject.org/cje/index.php/cje-rce/article/view/8128.