Lysenko, A., Volk, I., Serozhko, A. and Rybalko, O. (2018) “MULTIPLE THREE-WAWE RESONANCES IN TWO-STREAM FREE-ELECTRON LASER WITH A HELICAL ELECTRON BEAM”, Information and Telecommunication Sciences, (1), pp. 58–64. doi: 10.20535/2411-2976.12018.58-64.