Hierarchy of graph-diagonal states based on quantum discord and entanglement classification Mohammad Ali Jafarizadeh, Naser Karimi, Davood Amidi Sahlan, Ahmad Heshmati and Marziyeh Yahyavi Eur. Phys. J. D, 71 10 (2017) 254 Published online: 17 October 2017 DOI: 10.1140/epjd/e2017-80242-3