@article{PA_2021_10_3_a4,
     author = {S. Kamouche and H. Guebbai and M. Ghiat and S. Segni},
     title = {Generalized quadratic spectrum approximation in bounded and unbounded cases},
     journal = {Problemy analiza},
     pages = {53--70},
     year = {2021},
     volume = {10},
     number = {3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PA_2021_10_3_a4/}
}