Surender Kumar, Pooja Bhatia, Neelam. Numerical And Graphical Study Of The Average Queue Length For A Hierarchical Feedback Queuing System With Four Servers And The Limited Number Of Revisits To Any One Server. REDVET [Internet]. 2024Aug.14 [cited 2025Sep.11];25(2):1382-93. Available from: https://www.veterinaria.org/index.php/REDVET/article/view/1812