S. Rao, Vidya, et al. “Stability Analysis of Closed Loop TRMS With Observer Based Reliable H Infinity Controller Using Kharitonov’s Stability Theorem”. International Journal of Engineering & Technology, vol. 7, no. 2.21, Apr. 2018, pp. 106-11, https://doi.org/10.14419/ijet.v7i2.21.11846.