Â
Mardhiyana, D., & Nasution, N. B. (2018). "Kesiapan mahasiswa pendidikan matematika menggunakan e-learning dalam menghadapi era revolusi industri 4.0". Seminar Nasional Pendidikan Matematika Ahmad Dahlan, 31--35. Retrieved from http://seminar.uad.ac.id/index.php/sendikmad/article/view/1034/pdf.
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Mara Teresa Costado Dios and Jos Carlos Piero Charlo, (2019), "Face-to-Face vs. E-Learning Models in the COVID-19", Era: Survey Research in a Spanish University.
Marta Luisa Montiel Chamorro, (2018), "Comparing Online English Language Learning And Face-To-Face English Language Learning At El Bosque University In Colombia at Virginia Commonwealth University Richmond", Virginia May, 2018.
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Munir, (2009). Pembelajaran Jarak Jauh Berbasis teknologi Informasi Dan Komunikasi. Bandung: Alfabeta.
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Pallof, Rena M., Keith Pratt. (2007). "Building Online Learning Communities Effective Strategies for the Virtual Classroom. San Francisco, CA: JosseyBass".
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Restu Mufanti, Andi Susilo. (2016). "Establishing a Whatsapp Conversation: One of Innovations In English Language Teaching", Article is Published and Presented at The 63rd TEFLIN International Conference 2016. http//www.teflin2016.org. Â