1. Two queues in parallel;Haight;Biometrika,1958
2. Two similar queues in parallel;Kingman;Ann. Math. Stat.,1961
3. Boundary Value Problems in Queueing Systems Analysis;Cohen,1983
4. Random Walks in the Quarter-Plane: Algebraic Methods, Boundary Value Problems, Applications to Queueing Systems and Analytic Combinatorics;Fayolle,2017
5. Analysis of the symmetric shortest queue problem;Adan;Stoch. Models,1990