Jufriansah, Adi, Azmi Khusnani, Arief Hermanto, Mohammad Toifur, and Erwin Prasetyo. “The Existence of Fourier Coefficients and Periodic Multiplicity Based on Initial Values and One-Dimensional Wave Limits Requirements”. Jurnal Penelitian Fisika dan Aplikasinya (JPFA) 10, no. 2 (December 31, 2020): 146–157. Accessed May 2, 2024. https://journal.unesa.ac.id/index.php/jpfa/article/view/7286.