Backbone of credit relationships in the Japanese credit market Luca Marotta, Salvatore Miccichè, Yoshi Fujiwara, Hiroshi Iyetomi, Hideaki Aoyama, Mauro Gallegati and Rosario N Mantegna EPJ Data Sci., 5 1 (2016) 10 Published online: 22 March 2016 DOI: 10.1140/epjds/s13688-016-0071-7