Chuan Shao, Yang Li, Liang Wang, and Chen Jin. “Compact Wideband Parallel-Coupled Microstrip Line Bandpass Filter With In-Line Structure”. Applied Computational Electromagnetics Society Journal (ACES), vol. 32, no. 02, Aug. 2021, pp. 153-7, https://journals.riverpublishers.com/index.php/ACES/article/view/9741.