Tampubolon, Hotmaria, Farihah Farihah, Halida Hanim, and Halimul Bahri. 2022. “Development of Interactive E-Books for Production Unit Courses by Implementing a Hybrid Learning System ”. International Journal of Educational Research & Social Sciences 3 (6):2433-40. https://doi.org/10.51601/ijersc.v3i6.527.