Erratum to: Cottingham formula and nucleon polarisabilities J. Gasser, M. Hoferichter, H. Leutwyler and A. Rusetsky Eur. Phys. J. C, 80 5 (2020) 353 Published online: 02 May 2020 DOI: 10.1140/epjc/s10052-020-7905-y