Sinurat, J. N., B. A. Sihombing, S. O. Sirait, A. Agustina, H. Herman, and J. Batubara. “The Essential of Introducing TOEFL at Twelfth Grade Students of SMK GKPI 1 Pematangsiantar”. Abdimas Paspama, vol. 2, no. 1, Dec. 2023, pp. 35-41, https://paspama.org/index.php/abdimas/article/view/76.