8Pierre C.Mode Localization and Eigenvalue Loci Veering Phenomena in Disordered Structures [J].Journal of Sound and Vibration,1988,126:485-502.
9Triantafyllou M S,Triantafyllou G S.Frequency Coalescence and Mode Localization Phenomena:a Geometric Theory [J].Journal of Sound and Vibration,1991,150:485-500.