Darvinder Kumar. “Transient Analysis of a Queueing System Incorporating the Effects of Feedback, Randomly Changing States and Catastrophes”. International Journal of Intelligent Systems and Applications in Engineering, vol. 12, no. 23s, Dec. 2024, pp. 2589–2604, https://www.ijisae.org/index.php/IJISAE/article/view/7408.