@article{DAN_1989_305_6_a10,
     author = {\`E. I. Grigolyuk and B. L. Pelekh and O. S. Machuga},
     title = {Influence of defects on the normal frequencies of structurally inhomogeneous bodies},
     journal = {Doklady Akademii Nauk},
     pages = {1328--1330},
     publisher = {mathdoc},
     volume = {305},
     number = {6},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_305_6_a10/}
}