Non-Gaussian states with strong positive partial transpose Abdessamad Belfakir, Mustapha Ziane, Morad El Baz and Yassine Hassouni Eur. Phys. J. D, 73 10 (2019) 216 Published online: 24 October 2019 DOI: 10.1140/epjd/e2019-100368-6