@article{PORMA_1994__51_3_47282,
     author = {Buttazzo, Giuseppe and Faina, Loris},
     title = {The {Euler} equation for a class of nonconvex problems.},
     journal = {Portugaliae mathematica},
     pages = {405--419},
     publisher = {mathdoc},
     volume = {51},
     number = {3},
     year = {1994},
     zbl = {0824.49012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1994__51_3_47282/}
}