https://api.elsevier.com/content/article/pii/S0960077921000187doi:10.1016/j.chaos.2021.1106651-s2.0-S096007792100018710.1016/j.chaos.2021.110665S0960-0779(21)00018-7Black swans, extreme risks, and the e-pile model of self-organized criticality Chaos, Solitons & FractalsJournal096007792021-03-31March 20210falsefalse