“…For some recent contributions on fractional differential equations, see for example, [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] and the references therein. Especially, in [15], by means of Guo-Krasnosel'skiĭ's fixed point theorem, Zhao et al investigated the existence of positive solutions for the nonlinear fractional boundary value problem (BVP for short) In [16], relying on the Krasnosel'skiĭ's fixed point theorem as well as on the LeggettWilliams fixed point theorem, Kaufmann and Mboumi discussed the existence of positive solutions for the following fractional BVP D α 0+ u(t) + a(t)f (u(t)) = 0, 0 < t < 1, 1 < α ≤ 2, u(0) = 0, u (1) = 0.…”