Berman, Robert, et Liying Cheng. « English Academic Language Skills: Perceived Difficulties by Undergraduate and Graduate Students, and Their Academic Achievement ». Revue Canadienne De Linguistique appliquée, vol. 4, nᵒ 1, avril 2010, p. 25-40, https://journals.lib.unb.ca/index.php/CJAL/article/view/19830.