Mel’nyk, P. V., M. G. Nakhodkin, and M. I. Fedorchenko. “Influence of Changes in Defect States on the Properties of Si–Gd–O Photocathode”. Ukrainian Journal of Physics, vol. 62, no. 8, Dec. 2018, p. 692, doi:10.15407/ujpe62.08.0692.