@article{EJDE_2014__2014__a111,
     author = {Cadeddu,  Lucio and Farina,  Maria Antonietta and Porru,  Giovanni},
     title = {Optimization of the principal eigenvalue under mixed boundary conditions},
     journal = {Electronic journal of differential equations},
     year = {2014},
     volume = {2014},
     zbl = {1310.47024},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2014__2014__a111/}
}