Nadtayay, N., 		Najah, S., & 		Simpol, W.
2021 Dec 21.  The Development Of Learning Achievement In English Languages Of Grade6 Students In Covid-19 Situation By Applying The Flipped Classroom Concept Inverted. Journal Universitas Muhammadiyah Gresik Engineering, Social Science, and Health International Conference (UMGESHIC). [Online] 1:2