Loren Patrick Roberts Roberts, L., & Anistratov, D. Y. (2010). Nonlinear Weighted Flux Methods for Particle Transport Problems in Two-Dimensional Cartesian Geometry. NUCLEAR SCIENCE AND ENGINEERING, 165(2), 133–148. https://doi.org/10.13182/nse08-48 Roberts, L., & Anistratov, D. Y. (2007). Nonlinear weighted flux methods for particle transport problems. TRANSPORT THEORY AND STATISTICAL PHYSICS, 36(7), 589–608. https://doi.org/10.1080/00411450701703647