Coherent summation of Ka-band microwave beams produced by sub-gigawatt superradiance backward wave oscillators / K. A. Sharypov, A. A. El'chaninov, G. A. Mesyats [et.al.] // Applied physics letters. 2013. Vol. 103, № 13. P. 134103-1-134103-4. URL: http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000471148