Recent studies with electrons, positrons and positronium Michael J. Brunger, David B. Cassidy, Saša Dujko, Dragana Marić, Joan Marler, James P. Sullivan and Juraj Fedor Eur. Phys. J. D, 74 7 (2020) 158 Published online: 23 July 2020 DOI: 10.1140/epjd/e2020-10278-1