Public Perceptions of Online Learning in Developing Countries: A Study Using The ELK Stack for Sentiment Analysis on Twitter. - Satria Fadil Persada; Andri Oktavianto; Bobby Ardiansyah Miraja; Reny Nadlifatin; Prawira Fajarindra Belgiawan; A. A. N. Perwira Redi (Int. J. Emerg. Technol. Learn., 2020)