Gustavo Chávez George Turkiyyah Stefano Zampini David E. Keyes Parallel accelerated cyclic reduction preconditioner for three-dimensional elliptic PDEs with variable coefficients. 760-781 2018 344 J. Comput. Appl. Math. https://doi.org/10.1016/j.cam.2017.11.035 https://www.wikidata.org/entity/Q114202120 db/journals/jcam/jcam344.html#ChavezTZK18