SAEED, Aziz Thabit. Arab EFL Learners’ Acquisition of Modals. Research in Language, Poland, v. 7, p. 75–98, 2009. DOI: 10.2478/v10015-009-0006-5. Disponível em: https://www.czasopisma.uni.lodz.pl/research/article/view/8190. Acesso em: 16 oct. 2026.