Yang , YongHao , Wenrui and Zhang , Yong-Tao. (2022). A Continuous Finite Element Method with Homotopy Vanishing Viscosity for Solving the Static Eikonal Equation.
            <i>Communications in Computational Physics</i>. <i>31</i> (5).
            1402-1433.
         doi:10.4208/cicp.OA-2021-0164