The Implementation of Problem Based Learning Using Integrated Student’s Worksheet (LKPD) Towards Student’s Critical Thinking of 2nd Grade at SMP N 12 Padang. universe [Internet]. 16 Desember 2020 [dikutip 16 Agustus 2026];1(2):59-65. Tersedia pada: http://universe.ppj.unp.ac.id/index.php/universe/article/view/17