Wang , BinWu , XinyuanMeng , Fanwei and Fang , Yonglei. (2017). Exponential Fourier Collocation Methods for Solving First-Order Differential Equations.
            <i>Journal of Computational Mathematics</i>. <i>35</i> (6).
            711-736.
         doi:10.4208/jcm.1611-m2016-0596