On transition radiation by a low-energy relativistic “half-bare” electron N. F. Shul’ga, S. V. Trofymenko, S. Ya. Barsuk and O. A. Bezshyyko Eur. Phys. J. Plus, 134 7 (2019) 343 Published online: 19 July 2019 DOI: 10.1140/epjp/i2019-12870-0