QED and accretion flow models effect on optical appearance of Euler–Heisenberg black holesXiao-Xiong Zeng, Ke-Jian He, Guo-Ping Li, En-Wei Liang and Sen GuoEur. Phys. J. C, 82 8 (2022) 764DOI: https://doi.org/10.1140/epjc/s10052-022-10733-y