Enhancing entanglement of entangled coherent states via a f-deformed photon-addition operation B. Mojaveri, A. Dehghani and R. Jafarzadeh Bahrbeig Eur. Phys. J. Plus, 134 9 (2019) 456 Published online: 20 September 2019 DOI: 10.1140/epjp/i2019-12823-7