1. Birman M.Sh., Solomjak M.Z., Spectral theory of selfadjoint operators in Hilbert space. Mathematics and its Applications (Soviet Series). D. Reidel Publishing Co., Dordrecht, 1987.
2. Nazarov S.A., Plamenevsky B.A., Elliptic problems in domains with piecewise smooth boundaries, de Gruyter Expositions in Mathematics, 13. Walter de Gruyter & Co., Berlin, 1994.
3. Embedded trapped modes in water waves and acoustics
4. Trapping modes in the theory of surface waves
5. G. Cardone, T. Durante, S.A. Nazarov, Embedded eigenvalues of the Neumann problem in a strip with a box-shaped perturbation, arXiv:1512.06891 (submitted).