Khan, T. S., M. Jehangir, A. Niwaz, M. M. Khan, M. Shahzad, and M. S. Khan. “Statistical Approach: Understanding the Effects of Preview, Question, Read, Reflect, Recite, Review (PQ4R) on Academic Achievement of Students in English”. The Nucleus, vol. 55, no. 2, Oct. 2018, pp. 61-65, http://thenucleuspak.org.pk/index.php/Nucleus/article/view/246.