Georgina Maria Tinungki, Budi Nurwahyu. “The Implementation of Google Classroom As the E-Learning Platform for Teaching Non-Parametric Statistics During COVID-19 Pandemic in Indonesia”. International Journal of Advanced Science and Technology, Vol. 29, no. 04, June 2020, pp. 5793 -03, http://sersc.org/journals/index.php/IJAST/article/view/27089.