Lapin , AlexanderZhang , ShuhuaLapin , Sergey and Yan , Na. (2019). Analysis of Finite Difference Approximations of an Optimal Control Problem in Economics.
            <i>Advances in Applied Mathematics and Mechanics</i>. <i>11</i> (6).
            1358-1375.
         doi:10.4208/aamm.OA-2018-0186