@article {2009,
	title = {On viscosity solutions of Hamilton-Jacobi equations},
	journal = {Trans. Amer. Math. Soc. 361 (2009) 41-59},
	year = {2009},
	publisher = {American Mathematical Society},
	abstract = {We consider the Dirichlet problem for Hamilton-Jacobi equations and prove existence, uniqueness and continuous dependence on boundary data of Lipschitz continuous maximal viscosity solutions.},
	doi = {10.1090/S0002-9947-08-04557-1},
	url = {http://hdl.handle.net/1963/3420},
	author = {Sandro Zagatti}
}
@article {1994,
	title = {A version of Olech\\\'s lemma in a problem of the calculus of variations},
	journal = {SIAM J. Control Optim. 32 (1994) 1114-1127},
	year = {1994},
	publisher = {SIAM},
	abstract = {This paper studies the solutions of the minimum problem for a functional of the gradient under linear boundary conditions. A necessary and sufficient condition, based on the facial structure of the epigraph of the integrand, is provided for the continuous dependence of the solutions on boundary data.},
	doi = {10.1137/S0363012992234669},
	url = {http://hdl.handle.net/1963/3514},
	author = {Arrigo Cellina and Sandro Zagatti}
}
