PERKO, Gregor. What is the place of diaphasical, diatopical and diastratical variation in the Common European Framework of Reference for Languages?. Journal for Foreign Languages, Ljubljana, SI, v. 1, n. 1-2, p. 147–158, 2009. DOI: 10.4312/vestnik.1.147-158. Disponível em: https://journals.uni-lj.si/Vestnik/article/view/3461. Acesso em: 20 jan. 2026.