@article{Kolumbán_1977, title={Eine Verallgemeinerung des Satzes von Ljusternik: A generalization of Ljusternik’s theorem}, volume={6}, url={https://ictp.acad.ro/jnaat/journal/article/view/1977-vol6-no2-art4}, abstractNote={Not available.}, number={2}, journal={Anal. Numér. Théor. Approx.}, author={Kolumbán, I.}, year={1977}, month={Aug.}, pages={133–137} }