Jiao , YujianChen , Sheng and Guo , Benyu. (2015). Non-Isotropic Jacobi Spectral and Pseudospectral Methods in Three Dimensions.
            <i>Journal of Mathematical Study</i>. <i>48</i> (3).
            222-249.
         doi:10.4208/jms.v48n3.15.02