@article{JCA_1997_4_2_a10,
     author = {B. Kawohl and J. Lang},
     title = {Are {Some} {Optimal} {Shape} {Problems} {Convex?}},
     journal = {Journal of convex analysis},
     pages = {353--362},
     year = {1997},
     volume = {4},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/JCA_1997_4_2_a10/}
}