Sufficient conditions for the existence of nonnegative solutions of a nonlocal boundary value problem. - George L. Karakostas; P. Ch. Tsamatos (Appl. Math. Lett., 2002)

On a difference equation with min-max response. - George L. Karakostas; Stevo Stevic (Int. J. Math. Math. Sci., 2004)

Solvability of the Phi-Laplacian with nonlocal boundary conditions. - George L. Karakostas (Appl. Math. Comput., 2009)