A novel deterministic forecast model for the Covid-19 epidemic based on a single ordinary integro-differential equationFelix Köhler-Rieper, Claudius H. F. Röhl and Enrico De MicheliEur. Phys. J. Plus, 135 7 (2020) 599DOI: https://doi.org/10.1140/epjp/s13360-020-00608-0