Luo, Z., and S. Jin. “A Reduced-Order Extrapolation Spectral-Finite Difference Scheme Based on the POD Method for 2D Second-Order Hyperbolic Equations”. Mathematical Modelling and Analysis, vol. 22, no. 5, Sept. 2017, pp. 569-86, doi:10.3846/13926292.2017.1334714.