Rennita OD. The Differences of Improving Communication Ability and Mathematical Concepts Understanding between Students that Given Problem Based Learning and Discovery Learning at SMP Swasta Al-Hikmah Medan. ASSRJ [Internet]. 2018Nov.5 [cited 2024Nov.25];5(10). Available from: https://journals.scholarpublishing.org/index.php/ASSRJ/article/view/5467