@article{Vronskii_2006, title={On small oscillations of a compressible stratified liquid}, volume={58}, url={https://umj.imath.kiev.ua/index.php/umj/article/view/3559}, abstractNote={We study the structure of the spectrum and the completeness and basis property of a system of eigenvectors.}, number={12}, journal={Ukrains’kyi Matematychnyi Zhurnal}, author={Vronskii, B. M.}, year={2006}, month={Dec.}, pages={1614–1623} }