Nonlinear Ritz Approximation for the Camassa-Holm Equation by Using the Modify Lyapunov-Schmidt method . Baghdad Sci.J [Internet]. 2023 Oct. 1 [cited 2025 Jan. 3];20(5):1731. Available from: https://bsj.uobaghdad.edu.iq/index.php/BSJ/article/view/6932