Retnaningsih, Woro, Arif Nugroho, Dao Thi Hong Van, and Nur Hidayah Al Amin. “Booming the Vocabulary Acquisition by Using Flipped Classroom on EFL Learners’ PPA (Performance, Perception and Acceptance)”. Voices of English Language Education Society 6, no. 2 (October 31, 2022): 325–339. Accessed July 3, 2024. https://e-journal.hamzanwadi.ac.id/index.php/veles/article/view/6107.