“…Early research in this topic was done by Gnedenko and Kovalenko [1], Yechiali and Naor [2], Yadin and Syski [3], O'Cinneide and Purdue [4], Purdue [5], Neuts [6,7], and others. A brief history of the development of theory of queues in the RE, the reference list, and real life examples of queues in the RE can be found, for example, in the papers [8][9][10][11][12]. In [8], an unreliable / /1 retrial queue in a Markovian random environment is analyzed via matrix-analytic methods.…”