1. N. D. Handayani and M. Johan, “Correlation between problem faced in grammar and writing ability of EFL university students,” J. English Educ., vol. 4, no. 2, pp. 108–120, 2018.
2. S. Istiqomah, P. Raja, and B. Kadaryanto, “Correlation between grammar mastery and descriptive writing ability,” U-JET, vol. 3, no. 4, pp. 1–9, 2014.
3. I. Kamlasi and D. N. Nokas, “Grammatical errors in writing of the second class students of SMA Kristen 1 Soe,” METATHESIS, vol. 1, no. 1, pp. 130–140, 2017.
4. H. Aydoǧan and A. A. Akbarov, “The four basic language skills, whole language & integrated skill approach in mainstream university classrooms in Turkey,” Mediterr. J. Soc. Sci., vol. 5, no. 9, pp. 672–680, 2014, doi: https://doi.org/10.5901/mjss.2014.v5n9p672.
5. B. Adhiyatma, J. Jamiluddin, and N. Nadrun, “The correlation between students’ mastery of grammar and writing ability of the tenth grade,” e-journal English Lang. Teach. Soc., vol. 3, no. 2, pp. 1–12, 2015.