Citation: Ms. Ashbaugh et Rd. Benguria, A sharp bound for the ratio of the first two Dirichlet eigenvalues of a domain in a hemisphere of S-n, T AM MATH S, 353(3), 2000, pp. 1055-1087
Citation: Rd. Benguria et Mc. Depassier, Variational principle for limit cycles of the Rayleigh-van der Pol equation, PHYS REV E, 59(5), 1999, pp. 4889-4893