Rahmat Setiadi B, Sukardi T, . S. Mobile Technical Calculators with a Flipped Classroom for Sustainability Machining Process. IJET [Internet]. 2018 Jun. 20 [cited 2024 Apr. 29];7(3.2):741-6. Available from: https://www.sciencepubco.com/index.php/ijet/article/view/18740