Neelam Singla, Sonia Kalra. “A Two-State M/M/1 Retrial Queueing Model With Feedback”. International Journal of Advanced Science and Technology 29, no. 05 (April 23, 2020): 2608 - 2623. Accessed February 28, 2024. http://sersc.org/journals/index.php/IJAST/article/view/11158.