Mutalib, M. A., Z. Zakaria, and N. A. Shairi. 2017. “High Selectivity Microstrip Bandpass Filter Integrate With Ring Resonator Bandstop Filter”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC) 9 (2-13):39-42. https://jtec.utem.edu.my/jtec/article/view/2563.