• J. B. F. Adan, W. A. van de Waarsenburg, and J. Wessels, “Analyzing Ek/Er /c queues,” European Journal of Operational Research, vol. 92, no. 1, pp. 112–124, 1996. View at Publisher · View at Google Scholar · View at Scopus
• K.-H. Wang, “Optimal control of an M/Ek/1 queueing system with removable service station subject to breakdowns,” Journal of the Operational Research Society, vol. 48, no. 9, pp. 936–942, 1997. View at Publisher · View at Google Scholar · View at Scopus
• K.-H. Wang and M.-Y. Kuo, “Profit analysis of the M/Ek/1 machine repair problem with a non-reliable service station,” Computers & Industrial Engineering, vol. 32, no. 3, pp. 587–594, 1997. View at Publisher · View at Google Scholar · View at Scopus
• M. Jain and P. K. Agrawal, “M/Ek/1 Queueing system with working vacation,” Quality Technology & Quantitative Management, vol. 4, no. 4, pp. 455–470, 2007. View at Google Scholar
• D. Gross and C. M. Harris, Fundamentals of Queueing Theory, John Wiley & Sons, New York, NY, USA, 2nd edition, 2000.
• K.-H. Wang, K.-W. Chang, and B. D. Sivazlian, “Optimal control of a removable and non-reliable server in an infinite and a finite M/H2/1 queueing system,” Applied Mathematical Modelling, vol. 23, no. 8, pp. 651–666, 1999. View at Publisher · View at Google Scholar · View at Scopus
• K.-H. Wang, H.-T. Kao, and G. Chen, “Optimal management of a removable and non-reliable server in an infinite and a finite M/ H k /1 queueing system,” Quality Technology & Quantitative Management, vol. 1, no. 2, pp. 325–339, 2004. View at Google Scholar · View at MathSciNet
• H. Wang and K. L. Yen, “ptimal control of an M/Hk/1 queueing system with a removable server,” Mathematical Methods of Operations Research, vol. 57, pp. 255–262, 2003. View at Google Scholar
• R. Sharma, “Threshold N-Policy for MX/H2/1 queueing system with un-reliable server and vacations,” Journal of International Academy of Physical Sciences, vol. 14, no. 1, pp. 41–51, 2010. View at Google Scholar
• M. F. Neuts, Matrix Geometric Solutions in Stochastic Models: An Algorithmic Approach, The Johns Hopkins University Press, Baltimore, Md, USA, 1981. View at MathSciNet