“…Xie-Chen [26] presented a multiplicity result on the Kirchhoff-type problems in the bounded domain by using a similar strategy. A number of works dealt with the fractional differential equations [3,6,7,11,21] and some recent results on problem (1.3) can be seen in [4,5,10,12,13,14,15,16,22,23,27] and the references therein.…”