Malto, G. A. O., C. S. Dalida, and C. G. B. Lagunzad. “Flipped Classroom Approach in Teaching Biology: Assessing Students’ Academic Achievement and Attitude Towards Biology”. KnE Social Sciences, Vol. 3, no. 6, June 2018, pp. 540–554, doi:10.18502/kss.v3i6.2403.