Merits and constraints of low-K2 experimental data for the proton radius determination M. Hoballah, S. Cholak, R. Kunne, C. Le Galliard, D. Marchand, G. Quéméner, E. Voutier and J. van de Wiele Eur. Phys. J. A, 55 7 (2019) 112 Published online: 19 July 2019 DOI: 10.1140/epja/i2019-12799-9