@article{PA_1998_5_a8,
     author = {J. Sok\'o{\l} and W. Szumny},
     title = {Linear problems in the space of polynomials of degree at most 3},
     journal = {Problemy analiza},
     pages = {140--146},
     year = {1998},
     number = {5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PA_1998_5_a8/}
}