Kamil Jassim, H., H. Ali Naser, and A. Kleef Jiheel. “A New Efficient Method for Solving Helmholtz and Coupled Helmholtz Equations Involving Local Fractional Operators”. University of Thi-Qar Journal of Science, Vol. 6, no. 4, Apr. 2019, pp. 153-7, https://www.jsci.utq.edu.iq/index.php/main/article/view/81.