The stability of join-the-shortest-queue models with general input and   output processes
  The paper establishes necessary and sufficient conditions for stability of different join-the-shortest-queue models including load-balanced networks with general input and output processes. It is shown, that the necessary and sufficient condition for stability of load-balanced networks is associated with the solution of a linear programming problem precisely formulated in the paper. It is proved, that if the minimum of the objective function of that linear programming problem is less than 1, then the associated load-balanced network is stable. 
Vyacheslav M. Abramov