Christanti A, Purnomo R. The Implementation of Differentiated Instruction by Certified Teacher Leaders Across Educational Tiers: A Qualitative Case Study. SELL [Internet]. 2026 Aug. 26 [cited 2026 Aug. 26];11(2):147-58. Available from: http://publikasi.stkippgri-bkl.ac.id/index.php/SL/article/view/1310