1. Ambrosio L.: Existence theory for a new class of variational problems. Arch. Ration. Mech. Anal. 111(4), 291–322 (1990)
2. Ambrosio, L., Fusco, N., Pallara, D.: Functions of bounded variation and free discontinuity problems. Oxford Mathematical Monographs. The Clarendon Press, Oxford University Press, New York, 2000
3. Bandle, C., Wagner, A.: Second Variation of Domain Functionals and Applications to Problems with Robin Boundary Conditions. Report No. 65, Institute for Mathematics, RWTH Aachen University, 2013
4. Bossel M.-H.: Membranes élastiquement liées: extension du théorème de Rayleigh–Faber–Krahn et de l’inégalité de Cheeger. C. R. Acad. Sci. Paris Sér. I Math., 302(1), 47–50 (1986)
5. Bucur D., Daners D.: An alternative approach to the Faber–Krahn inequality for Robin problems. Calc. Var. Partial Differ. Equ. 37(1–2), 75–86 (2010)