@article{EJDE_2015__2015__a40,
     author = {Ferrara,  Massimiliano and Hadjian,  Armin},
     title = {Variational approach to fractional boundary value problems with two control parameters},
     journal = {Electronic journal of differential equations},
     year = {2015},
     volume = {2015},
     zbl = {1404.34028},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2015__2015__a40/}
}