Rakshit, P. C., G. Ghosh, P. K. Saha, and B. R. Nag. “8 GHz Tunable Gunn Oscillator in WR-137 Waveguide”. Defence Science Journal, vol. 33, no. 1, Jan. 2014, pp. 1-5, doi:10.14429/dsj.33.6093.