Teknowijoyo, F., Sunardi, S., & Gunarhadi, G. (2020). Analysis of Student Needs on the Development of Google Classroom-Based Digital Teaching Materials in Physics Subjects for Class VIII of Kalam Kudus Christian Middle School, Surakarta. International Journal of English Literature and Social Sciences, 5(4), 1209–1213. https://doi.org/10.22161/ijels.54.54