Ritonga, Abdul Kadir, Amat Mukhadis, Syamsul Hadi, and Dany M. Handarini. 2016. “Effects of Cooperative Learning Method Type Stad, Language Aptitude, and Intelligence on the Achievement English Hotel at Medan Tourism Academy”. International Journal of Social Sciences & Educational Studies 3 (2): 128-39. https://ijsses.tiu.edu.iq/index.php/ijsses/article/view/578.