1. S. Agmon. Lectures on exponential decay of solutions of second order elliptic equations. Bounds on eigenfunctions of N-body Schrödinger operators. Mathematical Notes of Princeton University.
2. F.A. Berezin, and M.A. Shubin. The Schrödinger equation. Mathematics and its Applications. Kluwer Academic Publishers (1991).
3. M. Brunaud, B. Helffer. Un problème de double puits provenant de la théorie statistico-mécanique des changements de phase, (ou relecture d’un cours de M. Kac). LMENS 1991.
4. L.S. Boulton. Non-selfadjoint harmonic oscillator semi-groups and pseudospectra. J. Operator Theory 47, p. 413–429 (2002).
5. A.B. Budko and M.A. Liberman. Stabilization of the Rayleigh–Taylor instability by convection in smooth density gradient: W.K.B. analysis. Phys. Fluids, p. 3499–3506 (1992).