Kanaharaj, A., and S. Malathi. “Effectiveness of Whatsapp Messenger Smartphone Application in Developing E-Teaching Competencies Among Teacher Trainees”. Shanlax International Journal of Education, Vol. 2, no. 4, Sept. 2014, pp. 52-59, https://shanlaxjournals.in/journals/index.php/education/article/view/2835.