@article {1990,
	title = {Shape optimization for Dirichlet problems: relaxed solutions and optimality conditions},
	journal = {Bull. Amer. Math. Soc. (N.S.) , 23 (1990), no.2, 531-535.},
	number = {SISSA;49/89/M},
	year = {1990},
	publisher = {SISSA Library},
	url = {http://hdl.handle.net/1963/809},
	author = {Giuseppe Buttazzo and Gianni Dal Maso}
}
