M Möller, B Zlnsou - Quaestiones Mathematicae, 2011 - ingentaconnect.com
We consider the eigenvalue problem y (4)(λ, x)−(gy′)′(λ, x)= λ 2 y (λ, x) with separated
boundary conditions B j (λ) y= 0 for j= 1,…, 4, where g∈ C 1 [0, a] is a real valued function, B …