Ke, Jau-Chuan. “The Optimal Control in Batch Arrival Queue With Server Vacations, Startup and Breakdowns”. Yugoslav Journal of Operations Research 14, no. 1 (March 1, 2004): 41–55. Accessed August 25, 2025. https://yujor.erc.fon.bg.ac.rs/index.php/yujor/article/view/122.