On optical soliton solutions of new Hamiltonian amplitude equation via Jacobi elliptic functions Asim Zafar, M. Raheel, Khalid K. Ali and Waseem Razzaq Eur. Phys. J. Plus, 135 8 (2020) 674 Published online: 24 August 2020 DOI: 10.1140/epjp/s13360-020-00694-0