“…However, for the scalar equation (2), as implied by the Sturm Separation Theorem, oscillation is essentially an interval property, i.e., if there exists a sequence of subintervals [a i , b i ] of [t 0 , ∞), a i → ∞, such that for each i, there exists a solution of (2) which has at least two zeros in [a i , b i ], then every solution of (2) is oscillatory no matter how "bad" the scalar equation (2)(or (3)) is on the remaining parts of [t 0 , ∞). Based on these facts, Kong [7] gives interval type criteria for the oscillation of system (2), which are extensions of those for scalar equations obtained by Kong [11]. Meanwhile, the oscillation of a system with damping has drawn less attention, Zheng [13] gave oscillation criteria for system (1), which generalize Theorem A.…”