Sebsibe, A. S., B. T. Dorra, and B. W. Beressa. “STUDENTS’ DIFFICULTIES AND MISCONCEPTIONS OF THE FUNCTION CONCEPT”. International Journal of Research -GRANTHAALAYAH, vol. 7, no. 8, Aug. 2019, pp. 181-96, doi:10.29121/granthaalayah.v7.i8.2019.656.