@article{CMJ_1999_49_3_a11,
     author = {John, Kamil},
     title = {U-ideals of factorable operators},
     journal = {Czechoslovak Mathematical Journal},
     pages = {607--616},
     year = {1999},
     volume = {49},
     number = {3},
     mrnumber = {1708346},
     zbl = {1008.46002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_1999_49_3_a11/}
}