Jasiński, Jerzy, and Mirosław Karpierz. “Solution of Coupled Nonlinear Schrödinger Equations in Focusing-Defocusing Medium by Modified Perturbation Theory”. Photonics Letters of Poland 13, no. 2 (June 30, 2021): 43–45. Accessed March 1, 2024. https://www.photonics.pl/PLP/index.php/letters/article/view/13-15.