New topological classification of bursting in multi-time-scale Chay–Cook model E. Zhang, Liao Yu and Zhuoqin Yang Eur. Phys. J. Spec. Top., 231 11-12 (2022) 2277-2288 Published online: 26 March 2022 DOI: 10.1140/epjs/s11734-022-00508-7