Dwikoranto, D., et al. “Mobile Learning to Improve Student Collaborative Skills: An Alternative to Online Learning in the Era of Covid-19 Pandemic”. Jurnal Penelitian Dan Pengkajian Ilmu Pendidikan: E-Saintika, vol. 4, no. 3, Nov. 2020, pp. 259-71, https://doi.org/10.36312/e-saintika.v4i3.314.