Encinas, A.H.H. et al. 2015. Efficient high-order finite difference methods for nonlinear Klein–Gordon equations. I: Variants of the phi-four model and the form-I of the nonlinear Klein–Gordon equation. Nonlinear Analysis: Modelling and Control. 20, 2 (Apr. 2015), 274–290. DOI:https://doi.org/10.15388/NA.2015.2.9.