Tan, G., M. Husain, and K. Tan. “High Performance Substrate Integrated Waveguide Bandstop Filter Using Dual-Radial Cavity Resonator”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 6, no. 2, Sept. 2015, pp. 5-9, https://jtec.utem.edu.my/jtec/article/view/460.