Safrizal S, Bahri S, Jumiarti D, Hakimi M. Development of a validation system (SVeR) based on the open journal system for testing the validity of learning tools. jitp [Internet]. 2026 Jun. 30 [cited 2026 Sep. 1];13(2):194-212. Available from: https://jurnal.uny.ac.id/index.php/jitp/article/view/95262