Analytical evaluation of elastic lepton-proton two-photon exchange in chiral perturbation theoryPoonam Choudhary, Udit Raha, Fred Myhrer and Dipankar ChakrabartiEur. Phys. J. A, 60 3 (2024) 69DOI: https://doi.org/10.1140/epja/s10050-023-01207-0