A new fuzzy fractional order model of transmission of Covid-19 with quarantine class Asma Hanif, A. I. K. Butt, Shabir Ahmad, Rahim Ud Din and Mustafa Inc Eur. Phys. J. Plus, 136 11 (2021) 1179 Published online: 24 November 2021 DOI: 10.1140/epjp/s13360-021-02178-1