Rivas-Ortiz, Iram Barbaro, et al. “An Extended Linear Discontinuous Method for One-Group Fixed Source Discrete Ordinates Problems With Isotropic Scattering in Slab Geometry”. Trends in Computational and Applied Mathematics, vol. 20, no. 1, May 2019, p. 61, doi:10.5540/tema.2019.020.01.61.