Perrodin, David D., and Narumon Somboon. “Is The Natural Order of Morpheme Acquisition Being Appropriately Presented In English Language Teaching Course Books?”. JEELS (Journal of English Education and Linguistics Studies) 6, no. 2 (November 25, 2019): 285–302. Accessed May 17, 2024. https://jurnalfaktarbiyah.iainkediri.ac.id/index.php/jeels/article/view/199.