Jufriansah, Adi, Azmi Khusnani, Arief Hermanto, Mohammad Toifur, and Erwin Prasetyo. 2020. “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 (2):146-57. https://doi.org/10.26740/jpfa.v10n2.p146-157.