HAROUN, Kh. M.; YAGOB, Arafa Ahmed Mohamed; ABD ALLAH, M. Dirar. Derivation of Klein – Gordon Equation for Frictional Medium. American Scientific Research Journal for Engineering, Technology, and Sciences, Jordan, v. 38, n. 1, p. 1–6, 2017. Disponível em: https://www.asrjetsjournal.org/American_Scientific_Journal/article/view/3526. Acesso em: 18 sep. 2025.