Dudin, A., A. Kazimirsky, V. Klimenok, L. Breuer, and U. Krieger. “The Queueing Model MAP|PH|1|N With Feedback Operating in a Markovian Random Environment”. Austrian Journal of Statistics, vol. 34, no. 2, Apr. 2016, pp. 101–110, doi:10.17713/ajs.v34i2.403.