Delay could induce the periodic behaviors through Hopf bifurcation, Are there any other bifurcations induced by delay that can lead to periodic behavior? Are there some references?
Delay can induces some complex periodic behaviour through various routes but analytical conditions for the same are rare as the changes take place through some global bifurcations. You can check the results related to the effect of time delay on existing chaotic dynamics as well as mixed mode oscillations.