Yildirim, Ozgur, and Meltem Uzun. “Weak Solvability of the Unconditionally Stable Difference Scheme for the Coupled Sine-Gordon System”. Nonlinear Analysis: Modelling and Control, vol. 25, no. 6, Nov. 2020, pp. 997-1014, https://doi.org/10.15388/namc.2020.25.20558.