Muhammad Rizky, M. Fahrul A, Agfa Oktaviana and Masbina Ajeng Lestari 2022. Testing the Website Performance of SMA Muhammadiyah 4 Yogyakarta Using K6 Tools and GTMetrix. Jurnal Sistem Informasi dan Teknologi Informasi. 1, 1 (Apr. 2022), 26–30.