This paper considers the output consensus problem of high-order leader-following multi-
agent systems with unknown nonlinear dynamics, in which the delayed and sampled outputs of the
system are the only available data. The unknown nonlinear dynamics are assumed to satisfy the
Lipschitz condition and the interconnected topologies are assumed to be undirected and connected.
A distributed observer-based output feedback controller is proposed for the system to reach output
consensus. Both of the bounds of the allowable delay and sampling period are also obtained. Sta-
bility analysis shows that the considered systems are globally exponentially stable under the output
feedback controller. Finally, a simulation example is given to validate our theoretical results.