Hayati, M. ., and H. S. . Vaziri. “Wide Stop-Band Microstrip Lowpass Filter With Sharp Roll-off Using Hairpin Resonators”. Applied Computational Electromagnetics Society Journal (ACES), vol. 28, no. 10, Sept. 2021, pp. 968-75, https://journals.riverpublishers.com/index.php/ACES/article/view/11373.