Tunnelling amplitudes through localised external potentials from Feynman diagram summation Rosemary Zielinski, Cédric Simenel and Patrick McGlynn Eur. Phys. J. C, 84 9 (2024) 992 Published online: 30 September 2024 DOI: 10.1140/epjc/s10052-024-13332-1