Celaya Villanueva, M. L. «The Form of the English Present Continuous in the Interlanguage of Learners of English As a Foreign Language». Babel – AFIAL : Aspectos De Filoloxía Inglesa E Alemá, n.º 2, mayo de 2019, pp. 115-22, https://revistas.uvigo.es/index.php/AFIAL/article/view/116.