@misc{Ignaczak_J._Upper_1971, author={Ignaczak, J.}, volume={23}, number={6}, copyright={Creative Commons Attribution BY 4.0 license}, journal={Archives of Mechanics}, address={Warszawa}, howpublished={online}, year={1971}, publisher={Polish Scientific Publishers IFTR}, language={eng}, language={pol}, language={rus}, type={Text}, title={Upper and lower bounds on the velocity of surface waves in a nonhomogenous isotropic elastic semi-space}, keywords={Mechanika stosowana - czasopisma [KABA]}, }