Hamiltonian form of an Extended Nonlinear Schrödinger Equation for Modelling the Wave field in a System with Quadratic and Cubic NonlinearitiesYu. V. Sedletsky and I.S. GandzhaMath. Model. Nat. Phenom., 17 (2022) 43DOI: https://doi.org/10.1051/mmnp/2022044
