1. Erlang, A.K., Probability and Telephone Calls, Nyt Tidsskrift Mat. Ser. B, 1909, vol. 20, pp. 33–39.
2. Metody razvitiya teorii teletrafika (Methods of Teletraffic Theory), Kharkevich, A.D., Ed., Moscow: Nauka, 1979.
3. Siforov, V.I., Razvitie Teorii Teletrafika v SSSR (Teletraffic Theory in the USSR) in [2], pp. 5–8.
4. Khinchin, A.Y., Raboty po matematicheskoi teorii massovogo obsluzhivaniya (Works on Mathematical Theory of Queues), Moscow: Fizmatlit, 1963.
5. Sevast’yanov, B.A., Ergodic Theorem for Markov Processes and Its Applications to Telephone Systems with Refusals, Theor. Veroyatn. Primenen., 1957, vol. 2, no. 1, pp. 106–116.