Relation between (e, e′) sum rules in 6, 7Li and 4He nuclei: Experiment and cluster model V. D. Efros, I. S. Timchenko and A. Yu. Buki Eur. Phys. J. A, 52 9 (2016) 275 Published online: 12 September 2016 DOI: 10.1140/epja/i2016-16275-x