Barida, Muya, Nur Hidayah, M. Ramli, Ahmad Taufiq, and Sunaryono Sunaryono. “An Investigation of Item Difficulties in Assertive Communication Based on Yogyakarta Cultural Values”. Pegem Journal of Education and Instruction 11, no. 4 (October 6, 2021): 100–109. Accessed September 16, 2025. https://www.pegegog.net/index.php/pegegog/article/view/1410.