Hopf bifurcation in a dynamic IS-LM model with time delay
  In this paper we investigate the impact of delayed tax revenues on the fiscal policy out-comes. Choosing the delay as a bifurcation parameter we study the direction and the stability of the bifurcating periodic solutions. With respect to the delay we show when the system is stable. Some numerical examples are finally given for justifying the theoretical results. 
Mihaela Neamtu, Dumitru Opris, Constantin Chilarescu