Teknowijoyo, Felixtian, Sunardi Sunardi, and Gunarhadi Gunarhadi. 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 (IJELS) 5 (4). https://journal-repository.com/index.php/ijels/article/view/2405.