“…In the recent literature, there have been numerous results on the oscillation for delay differential equation with discrete delays; see, for example, papers [1,4,[8][9][10][11][12][13][14][15][17][18][19][20][21][22][23], books [5,7,16] and references therein. But only a relatively few publications on oscillation for delay differential equation with distributed delay are found; see [2,3] and references cited ✩ This work was supported by NNSF of China.…”