The existence of positive solutions for Kirchhoff-type problems via the sub-supersolution method
Yan, Baoqiang, O’Regan, Donal, Agarwal, Ravi P.
Positive solutions for singular nonlocal boundary value problems involving integral conditions with derivative dependence
Yan, Baoqiang, O’Regan, Donal, Agarwal, Ravi P.